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Kosogor A, Soprunyuk V, Koraltan S, Golub V, Velyhotskyi D, Chernenko V, Hosoda H, Suess D, Schranz W, L'vov VA. Strong influence of magnetic field and non-uniform stress on elastic modulus and transition temperatures of twinned Ni-Fe(Co)-Ga alloy. Sci Rep 2024; 14:12199. [PMID: 38806550 DOI: 10.1038/s41598-024-62909-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 05/22/2024] [Indexed: 05/30/2024] Open
Abstract
The magnetization value and electric resistivity of the single-crystalline sample of Ni50Fe19Co4Ga27 shape memory alloy were measured. The elastic modulus was determined by the Dynamic Mechanical Analysis (DMA). The characteristic temperatures of martensitic transformation (MT) of the alloy were estimated from the temperature dependences of magnetization, electric resistivity and elastic modulus. A significant disparity between MT temperatures resulting from DMA and those estimated from magnetic and resistivity measurements was discovered. It was argued that the discrepancy is caused by the non-uniform mechanical stressing of twinned single crystal by the DMA analyzer. Moreover, the DMA measurements revealed a significant decrease of the elastic modulus of twinned martensite under the applied magnetic field of 1.5 kOe. To explain this effect, the temperature-dependent Young's modulus of twinned crystal lattice was computed. The computations showed that the experimentally observed field-induced change of the elastic modulus is caused by the stress-assisted detwinning of the crystal lattice by the applied magnetic field.
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Affiliation(s)
- Anna Kosogor
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Vienna, Austria.
- Institute of Magnetism NASU and MESU, Kyiv, 03142, Ukraine.
| | - Viktor Soprunyuk
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Vienna, Austria
| | - Sabri Koraltan
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Vienna, Austria
- Vienna Doctoral School in Physics, University of Vienna, Boltzmanngasse 5, 1090, Vienna, Austria
- Research Platform MMM Mathematics-Magnetism-Materials, University of Vienna, Vienna, Austria
| | - Vladimir Golub
- Institute of Magnetism NASU and MESU, Kyiv, 03142, Ukraine
| | | | - Volodymyr Chernenko
- BCMaterials, Basque Center for Materials, Applications and Nanostructures, University of Basque Country, UPV/EHU Science Park, 48940, Leioa, Spain
- Institute of Innovative Research (IIR), Tokyo Institute of Technology, Yokohama, 226-8503, Japan
- Ikerbasque, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Hideki Hosoda
- Institute of Innovative Research (IIR), Tokyo Institute of Technology, Yokohama, 226-8503, Japan
| | - Dieter Suess
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Vienna, Austria
| | - Wilfried Schranz
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Vienna, Austria
| | - Victor A L'vov
- Institute of Magnetism NASU and MESU, Kyiv, 03142, Ukraine
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2
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Zhang T, Yi L, Huang J, Zhang Y, Xu Y, Liu M, He X, Pan L. The effect of quenching and Mn substitution for Ni on the magnetic properties of Mn 25+xNi 50-xGa 25. Phys Chem Chem Phys 2023; 25:27364-27372. [PMID: 37791972 DOI: 10.1039/d3cp02341a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Ni-Mn based Heusler alloys have attracted widespread attention due to their novel physical properties. However, the structure of Mn2NiGa is metastable at room temperature, making it difficult to obtain its intrinsic physical properties and limiting its application. In this study, we obtained Mn2NiGa by replacing Ni in the precursor alloy Ni2MnGa with Mn and studied its magnetic properties, structures, and phase transitions with floating composition. In addition, we focused on the compositional segregation characteristics of Mn2NiGa caused by different heat treatment and quenching conditions. It was found that the samples quenched after annealing at 773 K for 48 hours exhibited abnormalities in magnetism, phase transformation, and structure. The further electron probe scanning characterization results reveal that the changes in these physical properties were related to component segregation caused by heat treatment.
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Affiliation(s)
- Tianfeng Zhang
- Hubei Engineering Research Center of Weak Magnetic-field Detection, College of Science, China Three Gorges University, Yichang 443002, China.
| | - Lizhi Yi
- Hubei Engineering Research Center of Weak Magnetic-field Detection, College of Science, China Three Gorges University, Yichang 443002, China.
| | - Jiaohong Huang
- State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization, Baotou Research Institute of Rare Earths, Baotou, 014030, China
| | - Yingde Zhang
- State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization, Baotou Research Institute of Rare Earths, Baotou, 014030, China
| | - Yunli Xu
- Hubei Engineering Research Center of Weak Magnetic-field Detection, College of Science, China Three Gorges University, Yichang 443002, China.
| | - Ming Liu
- Hubei Engineering Research Center of Weak Magnetic-field Detection, College of Science, China Three Gorges University, Yichang 443002, China.
| | - Xiong He
- Hubei Engineering Research Center of Weak Magnetic-field Detection, College of Science, China Three Gorges University, Yichang 443002, China.
| | - Liqing Pan
- Hubei Engineering Research Center of Weak Magnetic-field Detection, College of Science, China Three Gorges University, Yichang 443002, China.
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3
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Seguí C. Sequence and Characteristics of Atomic Ordering in Ni 2Mn 1-xCu xGa Ferromagnetic Shape Memory Alloys. MATERIALS (BASEL, SWITZERLAND) 2022; 15:8529. [PMID: 36500025 PMCID: PMC9736477 DOI: 10.3390/ma15238529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 06/17/2023]
Abstract
Post-quench atomic reordering processes undergone by Ni2Mn1-xCuxGa alloys have been characterized in detail. The obtained results corroborate the hypothesis that proposes an atomic ordering process additional to the B2↔L21 one, consisting of the relocation in the Mn sublattice of Cu atoms misplaced by quench in the Ni sublattice. In addition, the results suggest that the ordering of the Cu atoms and the L21 ordering can occur in different sequences depending on the starting state of order. The analysis of the saturation magnetization validates the occurrence of two types of atomic movements; the values corresponding to different post-quench stages have been compared with those calculated for different atomic configurations, supporting the relocation mechanism of Cu atoms as the most plausible mechanism. The effect of the quenching temperature on the reordering processes has been also studied, and an assessment of the degree of quenched disorder is provided, suggesting the existence of an order-disorder transition associated with Cu atoms ordering. Finally, the effect of the Cu amount has been analyzed, confirming that a greater amount of Cu intensifies the process associated to ordering of Cu atoms, which takes place even in martensite.
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Affiliation(s)
- Concepció Seguí
- Departament de Física, Campus Ctra, Universitat de les Illes Balears, Valldemossa, km 7,5, E-07122 Palma, Spain
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4
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Janovec J, Zelený M, Heczko O, Ayuela A. Localization versus delocalization of d-states within the [Formula: see text]MnGa Heusler alloy. Sci Rep 2022; 12:20577. [PMID: 36446814 PMCID: PMC9708842 DOI: 10.1038/s41598-022-23575-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 11/02/2022] [Indexed: 11/30/2022] Open
Abstract
We present calculations based on density-functional theory with improved exchange-correlation approaches to investigate the electronic structure of [Formula: see text]MnGa magnetic shape memory alloy prototype. We study the effects of hybrid functionals as well as a Hubbard-like correction parameter U on the structural, electronic and magnetic properties of the alloy. We show that the previously successful application of U on Mn should be extended by including U on Ni to describe the d localized electrons more accurately and in better agreement with experiments. The bonding interactions within this intermetallic alloy are analysed including the role of non-transition metal. We found that the strongest and most stabilizing bond is formed between the Ga-Ni pairs due to the delocalized s-s and p-s orbital hybridization. Our findings suggest that minimization of the over-delocalization error introduced by standard semi-local exchange-correlation functionals leads to a better description of the [Formula: see text]MnGa alloy. Furthermore we propose that the experimental total magnetic moment of Ni-Mn-Ga alloys could be increased after carefully selected heat treatment procedures.
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Affiliation(s)
- Jozef Janovec
- Donostia International Physics Center (DIPC), Manuel de Lardizabal 4, 20018 San Sebastián, Spain
- Centro de Física de Materiales-MPC CSIC-UPV/EHU, Manuel de Lardizabal 5, 20018 San Sebastián, Spain
- Faculty of Mechanical Engineering, Institute of Materials Science and Engineering, Brno University of Technology, Technická 2896/2, Brno, 61669 Czech Republic
| | - Martin Zelený
- Faculty of Mechanical Engineering, Institute of Materials Science and Engineering, Brno University of Technology, Technická 2896/2, Brno, 61669 Czech Republic
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, Prague, 12116 Czech Republic
| | - Oleg Heczko
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, Prague, 12116 Czech Republic
- FZU – Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, Prague, 18221 Czech Republic
| | - Andrés Ayuela
- Donostia International Physics Center (DIPC), Manuel de Lardizabal 4, 20018 San Sebastián, Spain
- Centro de Física de Materiales-MPC CSIC-UPV/EHU, Manuel de Lardizabal 5, 20018 San Sebastián, Spain
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5
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Kinetics of Reordering in Quenched Ni2Mn0.8Cu0.2Ga Ferromagnetic Shape Memory Alloys. METALS 2022. [DOI: 10.3390/met12050738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Quenched Ni2Mn1−xCuxGa ferromagnetic shape memory alloys undergo two consecutive post-quench ordering processes. The kinetics of order recovery has been analysed in detail for Ni2Mn0.8Cu0.2Ga, based on the calorimetric curves obtained during post-quench heating at constant rates. Isoconversional methods have been used to determine the activation energy, the pre-exponential factor, and the reaction model that best fits the two reordering processes. The kinetic analysis has been extended to samples quenched from different temperatures. The kinetic study shows that order improvement processes in quenched Ni2Mn0.8Cu0.2Ga alloys can be described by a first order reaction model, consistent with site-saturation nucleation and homogeneous diffusion-controlled growth, with apparent activation energies around 1.1 eV. The pre-exponential factors, especially those obtained for samples quenched from different temperatures, highlight the crucial role of the vacancies retained by high temperature quenching on the atomic reordering underlying the observed processes.
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6
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Cháb V, Drchal V, Máca F, Kudrnovský J, Cichoň S, Lančok J, Heczko O. Effect of Twinning on Angle-Resolved Photoemission Spectroscopy Analysis of Ni 49.7Mn 29.1Ga 21.2(100) Heusler Alloy. MATERIALS 2022; 15:ma15030717. [PMID: 35160661 PMCID: PMC8837013 DOI: 10.3390/ma15030717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 02/01/2023]
Abstract
To explain the observed features of k-space photoelectron images taken on off-stoichiometric Heusler Ni49.7Mn29.1Ga21.2 single-crystals in the cubic austenitic and pseudotetragonal martensitic phases, the images were simulated theoretically. Despite the moderate structural difference of both phases, there is large difference in photoemission spectra. Analysis of the final states' structure, matrix elements, and interface barrier scattering was performed to interpret discrepancies between the external photoemission of the austenite and martensite. The missing signal at the surface-normal emission of the martensitic phase is, ultimately, explained by repeated scatterings of escaping electrons on the interfaces between nanotwins.
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7
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Chatterjee S, Chatterjee S, Giri S, Majumdar S. Transport properties of Heusler compounds and alloys. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:013001. [PMID: 34521079 DOI: 10.1088/1361-648x/ac268c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Heusler compounds are a large group of intermetallic compositions with versatile material properties. In recent times, they are found to be important for their practical applications in the fields of spintronics and shape memory effect. Interestingly, their physical properties can be easily tuned by varying the valence electron concentration through proper doping and substitution. Empirical laws concerning the valence electron concentration, such as Slater-Pauling or Hume-Rothery rules are found to be useful in predicting their electronic, magnetic and structural properties quite accurately. Electrical transport measurements are simple laboratory-based techniques to gather a handful of information on the electronic properties of metals and semiconductors. The present review aimed to provide a comprehensive view of the transport in 3dand 4dtransition metal-based bulk Heusler compositions. The main emphasis is given on resistivity, magnetoresistance, Hall effect, thermopower and spin-dependent transport in spintronics devices. The review primarily focuses on magnetic Heusler compounds and alloys, albeit it also addresses several non-magnetic materials showing superconductivity or large thermopower.
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Affiliation(s)
- Snehashish Chatterjee
- School of Physical Sciences, Indian Association for the Cultivation of Science, 2A & B Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India
| | - Souvik Chatterjee
- UGC-DAE Consortium for Scientific Research, Kolkata Centre, Sector III, LB-8, Salt Lake, Kolkata 700106, India
| | - Saurav Giri
- School of Physical Sciences, Indian Association for the Cultivation of Science, 2A & B Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India
| | - Subham Majumdar
- School of Physical Sciences, Indian Association for the Cultivation of Science, 2A & B Raja S. C. Mullick Road, Jadavpur, Kolkata 700 032, India
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8
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Priolkar KR, Nevgi R, Dias ET, Nigam AK. Kinetic arrest of the ferromagnetic state in Mn[Formula: see text]GaC and Ni[Formula: see text]MnGa composite mixtures. Sci Rep 2021; 11:19588. [PMID: 34599259 PMCID: PMC8486870 DOI: 10.1038/s41598-021-99005-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 08/27/2021] [Indexed: 11/09/2022] Open
Abstract
The kinetics of the ferromagnetic to antiferromagnetic transition in Mn[Formula: see text]GaC can be arrested and its magnetic properties can be tuned by mixing a small amount ([Formula: see text] 10%) of Heusler Ni[Formula: see text]MnGa to Mn[Formula: see text]GaC. A detailed study of magnetic properties of composite mixtures of Mn[Formula: see text]GaC and Ni[Formula: see text]MnGa with different antiperovskite to Heusler ratio, reveals that the ferromagnetic Ni[Formula: see text]MnGa polarizes magnetic spins of the antiperovskite phase by creating a magnetic strain field in its vicinity. The Heusler phase acts as a defect centre whose influence on the magnetic properties of the majority antiperovskite phase progressively diminishes, creating a distribution of transition temperatures. Such strong interaction between the two phases of the mixture allows for tunability and control over the properties of such magneto-structurally transforming materials.
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Affiliation(s)
- K. R. Priolkar
- School of Physical and Applied Sciences, Goa University, Taleigao Plateau, Goa, 403206 India
| | - R. Nevgi
- School of Physical and Applied Sciences, Goa University, Taleigao Plateau, Goa, 403206 India
| | - E. T. Dias
- School of Physical and Applied Sciences, Goa University, Taleigao Plateau, Goa, 403206 India
| | - A. K. Nigam
- Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai, 400005 India
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9
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Ma Y, Yang Y, Gao Y, Hu Y. Optimization of spontaneous exchange bias in Mn-rich Heusler alloys. Phys Chem Chem Phys 2021; 23:17365-17373. [PMID: 34350446 DOI: 10.1039/d1cp01797g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
At low temperature, spontaneous (zero-field-cooled, SEB) and traditional (field-cooled) exchange bias effects may be induced in a series of NiMn-based Heusler alloys, and the exchange bias is commonly sensitive to alloying elements and compositions, while the mechanisms especially for SEB are still elusive. Therefore, the SEB in Mn-rich Heusler alloys with coexistence of ferromagnetic and antiferromagnetic exchange interactions is numerically studied by performing a modified Monte Carlo simulation. The intrinsic magnetocrystalline anisotropies (KAF), exchange interactions (JFM-AF and JAF-AF), and occupation probabilities (xFM) are directly tuned to establish their dependencies of zero-field-cooled/field-cooled thermomagnetic curves and zero-field-cooled magnetization hysteresis loops. The results indicate that the freezing temperature is monotonically enhanced with increasing KAF and varies nonmonotonically with other parameters, and at 5 K, the irreversibility arising from antiferromagnetic components becomes high enough to trigger SEB even though no spin glass state exists. The SEB is nonmonotonic with KAF, JFM-AF, JAF-AF, and xFM, and its maximum value will be obtained at KAF = 4.5 × 106 J m-3, JFM-AF = 5 meV, JAF-AF = -5 meV, or xFM = 0.3. On the contrary, the coercivity is also nonmonotonic with KAF and JFM-AF while monotonic with JAF-AF and xFM. The values of the SEB field are nearly one order of magnitude smaller than those of coercivity, consistent with experimental data. The magnetic relaxation properties are calculated to propose two factors, i.e., ferromagnetic-like domain between ferromagnetic and antiferromagnetic components and decay rate, to determine the final SEB. This work demonstrates the mechanisms to optimize SEB in Mn-rich Heusler alloys, and physically the results obtained are also suitable for other material systems with spontaneous ferromagnet/antiferromagnet phase separations.
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Affiliation(s)
- Yitian Ma
- Department of Physics, College of Sciences, Northeastern University, Shenyang 110819, China.
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10
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Veřtát P, Seiner H, Straka L, Klicpera M, Sozinov A, Fabelo O, Heczko O. Hysteretic structural changes within five-layered modulated 10M martensite of Ni-Mn-Ga(-Fe). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:265404. [PMID: 33902013 DOI: 10.1088/1361-648x/abfb8f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Abstract
Modulated structure of Ni-Mn-Ga-based alloys is decisive in their magnetic shape memory (MSM) functionality. However, the precise nature of their five-layered modulated 10M martensite is still an open question. We used x-ray and neutron diffraction experiments on single crystals to investigate structural changes within 10M-modulated martensite of the Ni50Mn27Ga22Fe1MSM alloy. The modulation vector gradually increases upon cooling from commensurateq= (2/5)g110, whereg110is the reciprocal lattice vector, to incommensurate withqup to pseudo-commensurateq= (3/7)g110. Upon heating, reverse changes are observed with a thermal hysteresis of ≈60 K. The same hysteretic behaviour was detected in the electrical resistivity and the effective elastic modulus. Scanning electron microscopy showed that the changes are accompanied by the refinement of thea/blaminate. These observations indicate that the commensurate state is a metastable form of 10M martensite. Upon cooling, this phase evolves through nanotwinning into a more irregular and more stable incommensurate structure.
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Affiliation(s)
- P Veřtát
- FZU - Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 18221 Prague 8, Czech Republic
- Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Trojanova 13, 11519 Prague 1, Czech Republic
| | - H Seiner
- Institute of Thermomechanics of the Czech Academy of Sciences, Dolejškova 1402/8, 18200 Prague 8, Czech Republic
| | - L Straka
- FZU - Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 18221 Prague 8, Czech Republic
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12116 Prague 2, Czech Republic
| | - M Klicpera
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 12116 Prague 2, Czech Republic
| | - A Sozinov
- Material Physics Laboratory, LUT University, Yliopistonkatu 34, 53850 Lappeenranta, Finland
| | - O Fabelo
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble cedex 9, France
| | - O Heczko
- FZU - Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 18221 Prague 8, Czech Republic
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11
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Full Variation of Site Substitution in Ni-Mn-Ga by Ferromagnetic Transition Metals. METALS 2021. [DOI: 10.3390/met11060850] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Systematic doping by transition elements Fe, Co and Ni on each site of Ni2MnGa alloy reveal that in bulk material the increase in martensitic transformation temperature is usually accompanied by the decrease in ferromagnetic Curie temperature, and vice versa. The highest martensitic transformation temperature (571 K) was found for Ni50.0Mn25.4(Ga20.3Ni4.3) with the result of a reduction in Curie temperature by 55 K. The highest Curie point (444 K) was found in alloy (Ni44.9Co5.1)Mn25.1Ga24.9; however, the transition temperature was reduced to 77 K. The dependence of transition temperature is better scaled with the Ne/a parameter (number of non-bonding electrons per atom) compared to usual e/a (valence electrons per atom). Ne/a dependence predicts a disappearance of martensitic transformation in (Ni45.3Fe5.3)Mn23.8Ga25.6, in agreement with our experiment. Although Curie temperature usually slightly decreases while the martensitic transition increases, there is no significant correlation of Curie temperature with e/a or Ne/a parameters. The doping effect of the same element is different for each compositional site. The cascade substitution is discussed and related to the experimental data.
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12
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Sakon T, Yamazaki J, Komori T, Kanomata T, Narumi Y, Hagiwara M, Nojiri H, Adachi Y. The Forced Magnetostrictions and Magnetic Properties of Ni 2MnX (X = In, Sn) Ferromagnetic Heusler Alloys. MATERIALS 2020; 13:ma13092017. [PMID: 32344877 PMCID: PMC7254384 DOI: 10.3390/ma13092017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/16/2020] [Accepted: 04/23/2020] [Indexed: 11/16/2022]
Abstract
Experimental studies into the forced magnetostriction, magnetization, and temperature dependence of permeability in Ni2MnIn and Ni2MnSn ferromagnetic Heusler alloys were performed according to the spin fluctuation theory of itinerant ferromagnetism proposed by Takahashi. We investigated the magnetic field (H) dependence of magnetization (M) at the Curie temperature TC, and at T = 4.2 K, which concerns the ground state of the ferromagnetic state. The M-H result at TC was analyzed by means of the H versus M5 dependence. At 4.2 K, it was investigated by means of an Arrott plot (H/M vs. M2) according to Takahashi’s theory. As for Ni2MnIn and Ni2MnSn, the spin fluctuation parameters in k-space (momentum space, TA) and that in energy space (frequency space, T0) obtained at TC and 4.2 K were almost the same. The average values obtained at TC and 4.2 K were TA = 342 K, T0 = 276 K for Ni2MnIn and TA = 447 K, T0 = 279 K for Ni2MnSn, respectively. The forced magnetostriction at TC was also investigated. The forced linear magnetostriction (ΔL/L) and the forced volume magnetostriction (ΔV/V) were proportional to M4, which followed Takahashi’s theory. We compared the forced volume magnetostriction ΔV/V and mechanical parameter, bulk modulus K. ΔV/V is inversely proportional to K. We also discuss the spin polarization of Ni2MnIn and other magnetic Heusler alloys. The pC/pS of Ni2MnIn was 0.860. This is comparable with that of Co2MnGa, which is a famous half-metallic alloy.
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Affiliation(s)
- Takuo Sakon
- Department of Mechanical and Systems Engineering, Faculty of Science and Technology, Ryukoku University, Otsu 520-2194, Shiga, Japan; (J.Y.); (T.K.)
- Correspondence:
| | - Junya Yamazaki
- Department of Mechanical and Systems Engineering, Faculty of Science and Technology, Ryukoku University, Otsu 520-2194, Shiga, Japan; (J.Y.); (T.K.)
| | - Takumi Komori
- Department of Mechanical and Systems Engineering, Faculty of Science and Technology, Ryukoku University, Otsu 520-2194, Shiga, Japan; (J.Y.); (T.K.)
| | - Takeshi Kanomata
- Research Institute for Engineering and Technology, Tohoku Gakuin University, Tagajo 985-8537, Miyagi, Japan;
| | - Yasuo Narumi
- Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan; (Y.N.); (M.H.)
| | - Masayuki Hagiwara
- Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan; (Y.N.); (M.H.)
| | - Hiroyuki Nojiri
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Miyagi, Japan;
| | - Yoshiya Adachi
- Graduate School of Science and Engineering, Yamagata University, Yonezawa 992-8510, Yamagata, Japan;
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13
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The Characteristic Properties of Magnetostriction and Magneto-Volume Effects of Ni 2MnGa-Type Ferromagnetic Heusler Alloys. MATERIALS 2019; 12:ma12223655. [PMID: 31698865 PMCID: PMC6888398 DOI: 10.3390/ma12223655] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 11/03/2019] [Accepted: 11/04/2019] [Indexed: 11/17/2022]
Abstract
In this article, we review the magnetostriction and magneto-volume effects of Ni2MnGa-type ferromagnetic Heusler alloys at the martensitic, premartensitic, and austenitic phases. The correlations of forced magnetostriction (ΔV/V) and magnetization (M), using the self-consistent renormalization (SCR) spin fluctuation theory of an itinerant electron ferromagnet proposed by Takahashi, are evaluated for the ferromagnetic Heusler alloys. The magneto-volume effect occurs due to the interaction between the magnetism and volume change of the magnetic crystals. The magnetic field-induced strain (referred to as forced magnetostriction) and the magnetization are measured, and the correlation of magnetostriction and magnetization is evaluated. The forced volume magnetostriction ΔV/V at the Curie temperature, TC is proportional to M4, and the plots cross the origin point; that is, (M4, ΔV/V) = (0, 0). This consequence is in good agreement with the spin fluctuation theory of Takahashi. An experimental study is carried out and the results of the measurement agree with the theory. The value of forced magnetostriction is proportional to the valence electron concentration per atom (e/a). Therefore, the forced magnetostriction reflects the electronic states of the ferromagnetic alloys. The magnetostriction near the premartensitic transition temperature (TP) induces lattice softening; however, lattice softening is negligible at TC. The forced magnetostriction at TC occurs due to spin fluctuations of the itinerant electrons. In the martensitic and premartensitic phases, softening of the lattice occurs due to the shallow hollow (potential barrier) of the total energy difference between the L21 cubic and modulated 10M or 14M structures. As a result, magnetostriction is increased by the magnetic field.
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14
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Zeng Q, Shen J, Zhang H, Chen J, Ding B, Xi X, Liu E, Wang W, Wu G. Electronic behaviors during martensitic transformations in all-d-metal Heusler alloys. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:425401. [PMID: 31226695 DOI: 10.1088/1361-648x/ab2bd8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
For solid-state phase transitions, the alterations of electronic structure driven by the band Jahn-Teller effect would play an essential role in the structural phase transitions and in switching the resistivity or magnetization states for potential applications. However, this evolution of the electronic structure and electronic transport during the martensitic transformations (MT) still lacks comprehensive investigations, especially in magnetic martensitic materials studied in recent years. In this work, we report a study on the electronic behaviors during the MT in a kind of all-d-metal Ni50-x Fe x Mn35Ti15 Heusler magnetic shape memory alloys, by combining x-ray diffraction, calorimetric, magnetic, transport measurements and calculations. Based on the magnetic MTs, the system shows large magnetocaloric effect and magnetoresistance. In the whole temperature range, the system is dominated by hole carriers in both parent and martensite phases. A sharp increase in carrier concentration is observed across the transformations. Meanwhile, the mobility of holes is depressed due to the lattice distortion. A picture of the characteristics of MTs has been proposed for general understanding and clues of the potential spintronic applications based on the magnetostructural phase transitions.
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Affiliation(s)
- Qingqi Zeng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China. University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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15
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Vir P, Kumar N, Borrmann H, Jamijansuren B, Kreiner G, Shekhar C, Felser C. Tetragonal Superstructure of the Antiskyrmion Hosting Heusler Compound Mn 1.4PtSn. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2019; 31:5876-5880. [PMID: 31423051 PMCID: PMC6694724 DOI: 10.1021/acs.chemmater.9b02013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/10/2019] [Indexed: 05/30/2023]
Abstract
Skyrmions in non-centrosymmetric magnets are vortex-like spin arrangements, viewed as potential candidates for information storage devices. The crystal structure and noncollinear magnetic structure together with magnetic and spin-orbit interactions define the symmetry of the skyrmion structure. We outline the importance of these parameters in the Heusler compound Mn1.4PtSn which hosts antiskyrmions, a vortex-like spin texture related to skyrmions. We overcome the challenge of growing large micro-twin-free single crystals of Mn1.4PtSn, which has proved to be the bottleneck for realizing bulk skyrmionic/antiskyrmionic states in a compound. The use of 5d-transition metal, platinum, together with manganese as constituents in the Heusler compound such as Mn1.4PtSn is a precondition for the noncollinear magnetic structure. Because of the tetragonal inverse Heusler structure, Mn1.4PtSn exhibits large magneto-crystalline anisotropy and D 2d symmetry, which are necessary for antiskyrmions. The superstructure in Mn1.4PtSn is induced by Mn-vacancies, which enable a ferromagnetic exchange interaction to occur. Mn1.4PtSn, the first known tetragonal Heusler superstructure compound, opens up a new research direction for properties related to the superstructure in a family containing thousands of compounds.
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16
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Xu X, Okada H, Chieda Y, Aizawa N, Takase D, Nishihara H, Sakon T, Han K, Ito T, Adachi Y, Kihara T, Kainuma R, Kanomata T. Magnetoresistance and Thermal Transformation Arrest in Pd 2Mn 1.4Sn 0.6 Heusler Alloys. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E2308. [PMID: 31330978 PMCID: PMC6678305 DOI: 10.3390/ma12142308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/12/2019] [Accepted: 07/15/2019] [Indexed: 11/17/2022]
Abstract
The magnetization, electric resistivity, and magnetoresistance properties of Pd 2 Mn 1 . 4 Sn 0 . 6 Heusler alloys were investigated. The Curie temperature of the parent phase, martensitic transformation temperatures, and magnetic field dependence of the martensitic transformation temperatures were determined. The magnetoresistance was investigated from 10 to 290 K, revealing both intrinsic and extrinsic magnetoresistance properties for this alloy. A maximum of about - 3 . 5 % of intrinsic magnetoresistance under 90 kOe and of about - 30 % of extrinsic magnetoresistance under 180 kOe were obtained. Moreover, the thermal transformation arrest phenomenon was confirmed in the Pd 2 Mn 1 . 4 Sn 0 . 6 alloy, and an abnormal heating-induced martensitic transformation (HIMT) behavior was observed.
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Affiliation(s)
- Xiao Xu
- Department of Materials Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan.
| | - Hironari Okada
- Faculty of Engineering, Tohoku Gakuin University, Tagajo 985-8537, Japan
| | - Yusuke Chieda
- Faculty of Engineering, Tohoku Gakuin University, Tagajo 985-8537, Japan
| | - Naoki Aizawa
- Faculty of Engineering, Tohoku Gakuin University, Tagajo 985-8537, Japan
| | - Daiki Takase
- Faculty of Engineering, Tohoku Gakuin University, Tagajo 985-8537, Japan
| | - Hironori Nishihara
- Faculty of Science and Technology, Ryukoku University, Otsu 520-2194, Japan
| | - Takuo Sakon
- Graduate School of Science and Engineering, Yamagata University, Yonezawa 992-8510, Japan
| | - Kwangsik Han
- Department of Materials Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Tatsuya Ito
- Department of Materials Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Yoshiya Adachi
- Graduate School of Science and Engineering, Yamagata University, Yonezawa 992-8510, Japan
| | - Takumi Kihara
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Ryosuke Kainuma
- Department of Materials Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Takeshi Kanomata
- Faculty of Engineering, Tohoku Gakuin University, Tagajo 985-8537, Japan
- Research Institute for Engineering and Technology, Tohoku Gakuin University, Tagajo 985-8537, Japan
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Zhang YJ, Liu ZH, Wu ZG, Ma XQ. Prediction of fully compensated ferrimagnetic spin-gapless semiconducting FeMnGa/Al/In half Heusler alloys. IUCRJ 2019; 6:610-618. [PMID: 31316805 PMCID: PMC6608636 DOI: 10.1107/s2052252519005062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 04/13/2019] [Indexed: 06/10/2023]
Abstract
Materials with full spin polarization that exhibit zero net magnetization attract great scientific interest because of their potential applications in spintronics. Here, the structural, magnetic and electronic properties of a C1 b -ordered FeMnGa alloy are reported using first-principles calculations. The results indicate that the corresponding band structure exhibits a considerable gap in one of the spin channels and a zero gap in the other thus allowing for high mobility of fully spin-polarized carriers. The localized magnetic moments of Fe and Mn atoms have an antiparallel arrangement leading to fully compensated ferrimagnetism, which possesses broken magnetic inversion symmetry. Such magnetic systems do not produce dipole fields and are extremely stable against external magnetic fields. Therefore, this will improve the performance of spintronic devices. Using this principle, similar band dispersion and compensated magnetic moments were predicted in a C1 b -ordered FeMnAl0.5In0.5 Heusler alloy.
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Affiliation(s)
- Y. J. Zhang
- School of Civil Engineering, Guangzhou University, Guangzhou 510006, People’s Republic of China
| | - Z. H. Liu
- Department of Physics, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
| | - Z. G. Wu
- School of Civil Engineering, Guangzhou University, Guangzhou 510006, People’s Republic of China
| | - X. Q. Ma
- Department of Physics, University of Science and Technology Beijing, Beijing 100083, People’s Republic of China
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18
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Investigation of the Itinerant Electron Ferromagnetism of Ni 2+xMnGa 1-x and Co₂VGa Heusler Alloys. MATERIALS 2019; 12:ma12040575. [PMID: 30769883 PMCID: PMC6416641 DOI: 10.3390/ma12040575] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 02/12/2019] [Accepted: 02/12/2019] [Indexed: 11/17/2022]
Abstract
Experimental investigations into the field dependence of magnetization and temperature dependences of magnetic susceptibility in Ni2+xMnGa1−x (x = 0.00, 0.02, 0.04) and Co2VGa Heusler alloy ferromagnets were performed following the spin fluctuation theory of itinerant ferromagnetism, called as “Takahashi theory”. We investigated the magnetic field dependence of magnetization at the Curie temperature TC, which is the critical temperature of the ferromagnetic–paramagnetic transition, and also at T = 5 K, which concerns the ground state of the ferromagnetic state. The field dependence of the magnetization was analyzed by means of the H vs. M5 dependence, and the field dependence of the ground state at 5 K was investigated by means of an Arrott plot (H/M vs. M2) according to the Takahashi theory. As for Ni2+xMnGa1−x, the spin fluctuation parameter in k-space (momentum space, TA) and that in energy space (T0) obtained at TC and 5 K were almost the same. On the contrary, as for Co2VGa, the H vs. M5 dependence was not shown at TC. We obtained TA and T0 by means of an Arrott plot at 5 K. We created a generalized Rhodes–Wohlfarth plot of peff/pS versus TC/T0 for the other ferromagnets. The plot indicated that the relationship between peff/pS and T0/TC followed Takahashi’s theory. We also discussed the spontaneous magnetic moment at the ground state, pS, which was obtained by an Arrott plot at 5 K and the high temperature magnetic moment, pC, at the paramagnetic phase. As for the localized ferromagnet, the pC/pS was 1. As for weak ferromagnets, the pC/pS was larger than 1. In contrast, the pC/pS was smaller than 1 by many Heusler alloys. This is a unique property of Heusler ferromagnets. Half-metallic ferromagnets of Co2VGa and Co2MnGa were in accordance with the generalized Rhodes–Wohlfarth plot with a km around 1.4. The magnetic properties of the itinerant electron of these two alloys appeared in the majority bands and was confirmed by Takahashi’s theory.
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Low temperature a/b nanotwins in Ni 50Mn 25+xGa 25-x Heusler alloys. Sci Rep 2018; 8:11943. [PMID: 30093683 PMCID: PMC6085376 DOI: 10.1038/s41598-018-30388-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/26/2018] [Indexed: 11/09/2022] Open
Abstract
We have found low temperature a/b nanotwins having (110) twinning plane in a five-layered modulated martensite phase of Ni50Mn25+xGa25-x (at. %) Heusler alloys and identified the particular region in phase diagram where the nanotwinning occurs. Evolution of the structure with decreasing temperature was studied by X-ray diffraction using single crystals exhibiting magnetic shape memory effect. The merging of (400) and (040) lines upon cooling for 2.6 < x < 3.5 indicated a/b nanotwinning originating from the refinement of initially coarse a/b twins. Refinement of the twins with decreasing temperature was observed directly using scanning electron microscopy. The prerequisite for nanotwinning is an extremely low twin boundary energy, which we estimated using first-principles calculations to be 0.16 meV/Å2. As the nanotwinning distorts the relation between the crystal lattice and the X-ray diffraction pattern, it should be taken into consideration in structural studies of Ni-Mn-Ga Heusler alloys.
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20
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Miroshkina O, Zagrebin M, Sokolovskiy V, Buchelnikov V. Structural and magnetic properties of heusler alloys Pd 2MnZ (Z=Ga, Ge, As): AB INITIO study. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201818505007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In this work, we report results of ab initio and Monte Carlo investigations of structural and magnetic properties in a series of Heusler compositions Pd2MnZ (Z = Ga, Ge, As). It was found that for Pd2MnGa and Pd2MnAs, the stable martensitic state is realized on the contrast with Pd2MnGe. The equilibrium lattice parameters for the series of Pd2MnZ (Z = Ga, Ge, As) compounds increase with increasing the number of valence electrons per atom (e/a ratio). Having calculated total magnetic moments and magnetic exchange parameters from ab initio methods, the Curie temperature for Pd2Mn-based alloys has been estimated in the framework of Monte Carlo simulations of Heisenberg model.
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21
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Weise B, Dutta B, Teichert N, Hütten A, Hickel T, Waske A. Role of disorder when upscaling magnetocaloric Ni-Co-Mn-Al Heusler alloys from thin films to ribbons. Sci Rep 2018; 8:9147. [PMID: 29904111 PMCID: PMC6002362 DOI: 10.1038/s41598-018-27428-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 06/01/2018] [Indexed: 11/09/2022] Open
Abstract
Research in functional magnetic materials often employs thin films as model systems for finding new chemical compositions with promising properties. However, the scale-up of thin films towards bulk-like structures is challenging, since the material synthesis conditions are entirely different for thin films and e.g. rapid quenching methods. As one of the consequences, the type and degree of order in thin films and melt-spun ribbons are usually different, leading to different magnetic properties. In this work, using the example of magnetocaloric Ni-Co-Mn-Al melt-spun ribbons and thin films, we show that the excellent functional properties of the films can be reproduced also in ribbons, if an appropriate heat treatment is applied, that installs the right degree of order in the ribbons. We show that some chemical disorder is needed to get a pronounced and sharp martensitic transition. Increasing the order with annealing improves the magnetic properties only up to a point where selected types of disorder survive, which in turn compromise the magnetic properties. These findings allow us to understand the impact of the type and degree of disorder on the functional properties, paving the way for a faster transfer of combinatorial thin film research towards bulk-like materials for magnetic Heusler alloys.
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Affiliation(s)
- B Weise
- Leibniz Institute for Solid State and Material Research Dresden, 01069, Dresden, Germany
- Institute for Material Science, TU Dresden, 01062, Dresden, Germany
| | - B Dutta
- Max-Planck-Institut für Eisenforschung GmbH, 40237, Düsseldorf, Germany
| | - N Teichert
- Center for Spinelectronic Materials and Devices, Department of Physics, Bielefeld University, 33615, Bielefeld, Germany
| | - A Hütten
- Center for Spinelectronic Materials and Devices, Department of Physics, Bielefeld University, 33615, Bielefeld, Germany
| | - T Hickel
- Max-Planck-Institut für Eisenforschung GmbH, 40237, Düsseldorf, Germany
| | - A Waske
- Leibniz Institute for Solid State and Material Research Dresden, 01069, Dresden, Germany.
- Institute for Material Science, TU Dresden, 01062, Dresden, Germany.
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22
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Zhang X, Zhang H, Qian M, Geng L. Enhanced magnetocaloric effect in Ni-Mn-Sn-Co alloys with two successive magnetostructural transformations. Sci Rep 2018; 8:8235. [PMID: 29844436 PMCID: PMC5974186 DOI: 10.1038/s41598-018-26564-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 05/15/2018] [Indexed: 11/29/2022] Open
Abstract
High magnetocaloric refrigeration performance requires large magnetic entropy change ΔS M and broad working temperature span ΔT FWHM . A fourth element doping of Co in ternary Ni-Mn-Sn alloy may significantly enhance the saturation magnetization of the alloy and thus enhance the ΔS M . Here, the effects of Co-doping on the martensite transformation, magnetic properties and magnetocaloric effects (MCE) of quaternary Ni47-xMn43Sn10Cox (x = 0, 6, 11) alloys were investigated. The martensite transformation temperatures decrease while austenite Curie point increases with Co content increasing to x = 6 and 11, thus broadening the temperature window for a high magnetization austenite (13.5, 91.7 and 109.1 A·m2/kg for x = 0, 6 and 11, respectively). Two successive magnetostructural transformations (A → 10 M and A → 10 M + 6 M) occur in the alloy x = 6, which are responsible for the giant magnetic entropy change ΔS M = 29.5 J/kg·K, wide working temperature span ΔT FWHM = 14 K and large effective refrigeration capacity RC eff = 232 J/kg under a magnetic field of 5.0 T. These results suggest that Ni40.6Mn43.3Sn10.0Co6.1 alloy may act as a potential solid-state magnetic refrigerant working at room temperature.
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Affiliation(s)
- Xuexi Zhang
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China.
| | - Hehe Zhang
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Mingfang Qian
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Lin Geng
- School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
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23
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Singh S, Dutta B, D'Souza SW, Zavareh MG, Devi P, Gibbs AS, Hickel T, Chadov S, Felser C, Pandey D. Robust Bain distortion in the premartensite phase of a platinum-substituted Ni 2MnGa magnetic shape memory alloy. Nat Commun 2017; 8:1006. [PMID: 29044121 PMCID: PMC5647333 DOI: 10.1038/s41467-017-00883-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 08/02/2017] [Indexed: 12/05/2022] Open
Abstract
The premartensite phase of shape memory and magnetic shape memory alloys (MSMAs) is believed to be a precursor state of the martensite phase with preserved austenite phase symmetry. The thermodynamic stability of the premartensite phase and its relation to the martensitic phase is still an unresolved issue, even though it is critical to the understanding of the functional properties of MSMAs. We present here unambiguous evidence for macroscopic symmetry breaking leading to robust Bain distortion in the premartensite phase of 10% Pt-substituted Ni2MnGa. We show that the robust Bain-distorted premartensite (T2) phase results from another premartensite (T1) phase with preserved cubic-like symmetry through an isostructural phase transition. The T2 phase finally transforms to the martensite phase with additional Bain distortion on further cooling. Our results demonstrate that the premartensite phase should not be considered as a precursor state with the preserved symmetry of the cubic austenite phase.
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Affiliation(s)
- Sanjay Singh
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187, Dresden, Germany.
- School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, 221005, India.
| | - B Dutta
- Max-Planck-Institut für Eisenforschung Max-Planck-Strasse 1, 40237, Düsseldorf, Germany
| | - S W D'Souza
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187, Dresden, Germany
| | - M G Zavareh
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187, Dresden, Germany
| | - P Devi
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187, Dresden, Germany
| | - A S Gibbs
- ISIS Pulsed Neutron Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11-0QX, UK
| | - T Hickel
- Max-Planck-Institut für Eisenforschung Max-Planck-Strasse 1, 40237, Düsseldorf, Germany
| | - S Chadov
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187, Dresden, Germany
| | - C Felser
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187, Dresden, Germany
| | - D Pandey
- School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, 221005, India
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24
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Lázpita P, Barandiarán JM, Gutiérrez J, Mondelli C, Sozinov A, Chernenko VA. Polarized Neutron Study of Ni-Mn-Ga Alloys: Site-Specific Spin Density Affected by Martensitic Transformation. PHYSICAL REVIEW LETTERS 2017; 119:155701. [PMID: 29077463 DOI: 10.1103/physrevlett.119.155701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Indexed: 06/07/2023]
Abstract
Polarized neutron scattering has been used to obtain the magnetic moment at specific crystallographic sites of the austenitic and martensitic phases of two nonstoichiometric Ni-Mn-Ga single crystals with close composition. These alloys have been chosen because they exhibit different structures in the paramagnetic state and inverse positions of the respective martensitic transformation and Curie temperature. The diffraction analysis revealed a remarkable result: Despite the similar alloy composition, the magnetic moments of Mn are quite different for the two alloys at the same crystallographic position. Furthermore, such a difference enabled us to assess that the exchange coupling between Mn atoms switches from ferro- to antiferromagnetic at a distance between 2.92 and 3.32 Å in the martensite. These results are of great importance to guide first principles calculations that, up to now, have not been contrasted with experiments at the atomic level.
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Affiliation(s)
- P Lázpita
- Dpto Electricidad y Electrónica, UPV/EHU, 48940 Leioa, Spain
| | - J M Barandiarán
- Dpto Electricidad y Electrónica, UPV/EHU, 48940 Leioa, Spain
- BCMaterials, Basque Center for Materials, Applications and Nanostructures, 48160 Derio, Spain
| | - J Gutiérrez
- Dpto Electricidad y Electrónica, UPV/EHU, 48940 Leioa, Spain
- BCMaterials, Basque Center for Materials, Applications and Nanostructures, 48160 Derio, Spain
| | - C Mondelli
- CNR-IOM, c/o Institute Laue Langevin, 38042 Grenoble, France
| | - A Sozinov
- Material Physics Laboratory, Lappeenranta University of Technology, Laitaatsillantie 3, 57170 Savonlinna, Finland
| | - V A Chernenko
- Dpto Electricidad y Electrónica, UPV/EHU, 48940 Leioa, Spain
- BCMaterials, Basque Center for Materials, Applications and Nanostructures, 48160 Derio, Spain
- Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain
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25
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26
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Pereira MJ, Amaral JS, Silva NJO, Amaral VS. Nano-Localized Thermal Analysis and Mapping of Surface and Sub-Surface Thermal Properties Using Scanning Thermal Microscopy (SThM). MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2016; 22:1270-1280. [PMID: 27869043 DOI: 10.1017/s1431927616011867] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Determining and acting on thermo-physical properties at the nanoscale is essential for understanding/managing heat distribution in micro/nanostructured materials and miniaturized devices. Adequate thermal nano-characterization techniques are required to address thermal issues compromising device performance. Scanning thermal microscopy (SThM) is a probing and acting technique based on atomic force microscopy using a nano-probe designed to act as a thermometer and resistive heater, achieving high spatial resolution. Enabling direct observation and mapping of thermal properties such as thermal conductivity, SThM is becoming a powerful tool with a critical role in several fields, from material science to device thermal management. We present an overview of the different thermal probes, followed by the contribution of SThM in three currently significant research topics. First, in thermal conductivity contrast studies of graphene monolayers deposited on different substrates, SThM proves itself a reliable technique to clarify the intriguing thermal properties of graphene, which is considered an important contributor to improve the performance of downscaled devices and materials. Second, SThM's ability to perform sub-surface imaging is highlighted by thermal conductivity contrast analysis of polymeric composites. Finally, an approach to induce and study local structural transitions in ferromagnetic shape memory alloy Ni-Mn-Ga thin films using localized nano-thermal analysis is presented.
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Affiliation(s)
- Maria J Pereira
- CICECO - Aveiro Institute of Materials and Physics Department,University of Aveiro,Campus Universitário de Santiago,3810-193 Aveiro,Portugal
| | - Joao S Amaral
- CICECO - Aveiro Institute of Materials and Physics Department,University of Aveiro,Campus Universitário de Santiago,3810-193 Aveiro,Portugal
| | - Nuno J O Silva
- CICECO - Aveiro Institute of Materials and Physics Department,University of Aveiro,Campus Universitário de Santiago,3810-193 Aveiro,Portugal
| | - Vitor S Amaral
- CICECO - Aveiro Institute of Materials and Physics Department,University of Aveiro,Campus Universitário de Santiago,3810-193 Aveiro,Portugal
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27
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Steiner J, Lisfi A, Kakeshita T, Fukuda T, Wuttig M. Unique magnetostriction of Fe 68.8Pd 31.2 attributable to twinning. Sci Rep 2016; 6:34259. [PMID: 27688053 PMCID: PMC5043241 DOI: 10.1038/srep34259] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 09/08/2016] [Indexed: 11/09/2022] Open
Abstract
Fe68.8Pd31.2 exhibits an anomalously large magnetostriction of ~400 ppm at room temperature as well as linear, isotropic, and hysteresis free magnetization behavior. This near perfectly reversible magnetic response is attributable to the presence of a large number of premartensitic magnetoelastic twin clusters present in the system made possible through the elastic softening that occurs near a martensitic transformation temperature of 252 K. It is proposed that the twin clusters in the material reduce both internal elastic and magnetic energy, causing the elastic and magnetic behavior of the material to be intimately linked. In such a framework, the anisotropy energy becomes extremely low causing the material to bear no crystalline dependence on magnetization, and application of a magnetic field causes simultaneous magnetic and twin domain movement which relaxes the system.
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Affiliation(s)
- Jake Steiner
- University of Maryland, Department of Materials Science and Engineering, College Park, MD 20902, USA
| | - Abdellah Lisfi
- Morgan State Univeristy, Department of Physics, Baltimore, MD 21251, USA
| | - Tomoyuki Kakeshita
- Osaka University, Department of Materials Science and Engineering, Suita, Osaka 565-0871, Japan
| | - Takashi Fukuda
- Osaka University, Department of Materials Science and Engineering, Suita, Osaka 565-0871, Japan
| | - Manfred Wuttig
- University of Maryland, Department of Materials Science and Engineering, College Park, MD 20902, USA
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28
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Barker S, Rhoads E, Lindquist P, Vreugdenhil M, Müllner P. Magnetic Shape Memory Micropump for Submicroliter Intracranial Drug Delivery in Rats. J Med Device 2016. [DOI: 10.1115/1.4034576] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Point-of-care diagnostic devices, micrototal analysis (μTAS) systems, lab-on-a-chip development, and biomedical research rely heavily upon microfluidic management and innovative micropump design. Here, we describe the design and prototype deployment of a magnetic shape memory (MSM) micropump capable of submicroliter per minute flow rates. The pump contains no valves or moving parts in the fluid channel and is capable of bidirectional fluid transport. This pump was employed as the mechanism to deliver small intracranial dosages of ketamine and tetrodotoxin (TTX) at 0.33 μl/min during in vivo electrophysiological recordings in anesthetized rats, performing to required specifications.
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Affiliation(s)
- Samuel Barker
- Department of Mechanical and Biomedical Engineering, Department of Material Science and Engineering, Boise State University, 1910 University Drive, Mail Stop 2090, Boise, ID 83725-2090 e-mail:
| | - Eric Rhoads
- Department of Mechanical and Biomedical Engineering, Department of Material Science and Engineering, Boise State University, 1910 University Drive, Mail Stop 2090, Boise, ID 83725-2090 e-mail:
| | - Paul Lindquist
- Department of Material Science and Engineering, Boise State University, 1910 University Drive, Mail Stop 2090, Boise, ID 83725-2090 e-mail:
| | - Martin Vreugdenhil
- School of Clinical and Experimental Medicine, University of Birmingham, Vincent Drive, Birmingham B15 2TT, UK e-mail:
| | - Peter Müllner
- Department of Material Science and Engineering, Boise State University, 1910 University Drive, Mail Stop 2090, Boise, ID 83725-2090 e-mail:
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Özkale B, Mushtaq F, Fornell J, Chatzipirpiridis G, Martin LH, Sort J, Müller CM, Pellicer E, Nelson BJ, Pané S. Single step electrosynthesis of NiMnGa alloys. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.04.071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Li Z, Xu K, Zhang Y, Tao C, Zheng D, Jing C. Two successive magneto-structural transformations and their relation to enhanced magnetocaloric effect for Ni55.8Mn18.1Ga26.1 Heusler alloy. Sci Rep 2015; 5:15143. [PMID: 26450663 PMCID: PMC4598732 DOI: 10.1038/srep15143] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 09/21/2015] [Indexed: 11/28/2022] Open
Abstract
In the present work, two successive magneto-structural transformations (MSTs) consisting of martensitic and intermartensitic transitions have been observed in polycrystalline Ni55.8Mn18.1Ga26.1 Heusler alloy. Benefiting from the additional latent heat contributed from intermediate phase, this alloy exhibits a large transition entropy change ΔStr with the value of ~27 J/kg K. Moreover, the magnetocaloric effect (MCE) has been also evaluated in terms of Maxwell relation. For a magnetic field change of 30 kOe, it was found that the calculated value of refrigeration capacity in Ni55.8Mn18.1Ga26.1 attains to ~72 J/kg around room temperature, which significantly surpasses those obtained for many Ni-Mn based Heusler alloys in the same condition. Such an enhanced MCE can be ascribed to the fact that the isothermal entropy change ΔST is spread over a relatively wide temperature interval owing to existence of two successive MSTs for studied sample.
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Affiliation(s)
- Zhe Li
- College of Physics and Electronic Engineering, Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011, P.R. China
| | - Kun Xu
- College of Physics and Electronic Engineering, Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011, P.R. China
| | - Yuanlei Zhang
- College of Physics and Electronic Engineering, Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011, P.R. China
| | - Chang Tao
- College of Physics and Electronic Engineering, Key Laboratory for Advanced Functional and Low Dimensional Materials of Yunnan Higher Education Institute, Qujing Normal University, Qujing 655011, P.R. China
| | - Dong Zheng
- Department of Physics, Shanghai University, Shanghai 200444, P.R. China
| | - Chao Jing
- Department of Physics, Shanghai University, Shanghai 200444, P.R. China
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Zhu S, Ye M, Shirai K, Taniguchi M, Ueda S, Miura Y, Shirai M, Umetsu RY, Kainuma R, Kanomata T, Kimura A. Drastic change in density of states upon martensitic phase transition for metamagnetic shape memory alloy Ni2Mn(1+x)In(1-x). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:362201. [PMID: 26289060 DOI: 10.1088/0953-8984/27/36/362201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have unravelled the electronic structure of a class of metamagnetic shape memory alloy Ni2Mn1+x In1-x by combining bulk-sensitive hard x-ray photoelectron spectroscopy and first-principles density-functional calculations. A sharp drop in the Ni 3d e(g) density of states forming a pseudogap in the martensitic phase transition (MPT) for x = 0.36 has been observed near the Fermi level. As a feature of MPT, hysteretic behaviour of this drop has been confirmed in both cooling and warming. This pseudogap is responsible for the giant negative magnetoresistance. The experimental result is well reproduced by the first principle calculation. We have also clarified theoretically that the MPT is linked to a competition of ferromagnetic and anti-ferromagnetic coupling between ordinary and anti-site Mn atoms.
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Affiliation(s)
- Siyuan Zhu
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
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Effects of Annealing on the Martensitic Transformation of Ni-Based Ferromagnetic Shape Memory Heusler Alloys and Nanoparticles. METALS 2015. [DOI: 10.3390/met5020484] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Paul S, Sanyal B, Ghosh S. First-principles study of the lattice instabilities in Mn2NiX (X = Al, Ga, In, Sn) magnetic shape memory alloys. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:035401. [PMID: 25537964 DOI: 10.1088/0953-8984/27/3/035401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Using first-principles based density functional theory, we have investigated the structural instabilities in the austenite phases of Mn(2)NiX (X = Al, Ga, In, Sn) magnetic shape memory alloys. A complete softening is observed in the acoustic TA(2) branches for all the materials along [ξξ0] directions leading to instability in the austenite structure which effectively stabilizes into martensitic structure. The reasons behind this softening are traced back to the repulsion from the optical T(2g) branches and to the nesting features in the Fermi surfaces. The vibrational density of states, the force constants and the elastic moduli are also computed and analyzed, which reconfirm the underlying mechanism behind the instabilities. The results indicate that the phonon anomalies are related to the occurrence of possible pre-martensitic phases which can be quite complex.
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Affiliation(s)
- Souvik Paul
- Department of Physics, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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Zagrebin MA, Sokolovskiy VV, Buchelnikov VD, Klyuchnikova MA. First Principles Investigation of Magnetic Properties of Fe-Ni-Mn-Al Heusler Alloys. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.phpro.2015.12.162] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Magnetic Properties of the Ferromagnetic Shape Memory Alloys Ni 50+xMn 27-xGa 23 in Magnetic Fields. MATERIALS 2014; 7:3715-3734. [PMID: 28788645 PMCID: PMC5453230 DOI: 10.3390/ma7053715] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 04/02/2014] [Accepted: 05/04/2014] [Indexed: 11/19/2022]
Abstract
Thermal strain, permeability, and magnetization measurements of the ferromagnetic shape memory alloys Ni50+xMn27−xGa23 (x = 2.0, 2.5, 2.7) were performed. For x = 2.7, in which the martensite transition and the ferromagnetic transition occur at the same temperature, the martensite transition starting temperature TMs shift in magnetic fields around a zero magnetic field was estimated to be dTMs/dB = 1.1 ± 0.2 K/T, thus indicating that magnetic fields influences martensite transition. We discussed the itinerant electron magnetism of x = 2.0 and 2.5. As for x = 2.5, the M4vs. B/M plot crosses the origin of the coordinate axis at the Curie temperature, and the plot indicates a good linear relation behavior around the Curie temperature. The result is in agreement with the theory by Takahashi, concerning itinerant electron ferromagnets.
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Mohd Jani J, Leary M, Subic A, Gibson MA. A review of shape memory alloy research, applications and opportunities. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.matdes.2013.11.084] [Citation(s) in RCA: 2185] [Impact Index Per Article: 218.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Sarafidis C, Gjoka M, Kalogirou O, Lupu N, Ababei G, Niarchos D. Structural and Magnetic Properties of Fe Doped Mn-Ga Ribbons. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20147503004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Barandiaran JM, Chernenko VA, Cesari E, Salas D, Gutierrez J, Lazpita P. Magnetic field and atomic order effect on the martensitic transformation of a metamagnetic alloy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:484005. [PMID: 24201042 DOI: 10.1088/0953-8984/25/48/484005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The martensitic transformation (MT) of metamagnetic shape memory alloys is very sensitive to the applied magnetic field and atomic order. We analyze the alloy Ni50Mn34.5In15.5 in magnetic fields up to 13 T. The alloy has been prepared both in an ordered state by slow cooling, and in a disordered state by rapid quenching. In both cases the dependence of the martensitic transition temperature on the field is highly nonlinear. Such departure from linearity is due to a decrease of the entropy change at the transition, ΔS, with the applied field. This can be explained by the ordering effect of the magnetic field on the frustrated magnetic structure of the alloy in the martensitic phase. Compliance with a recent model, relying on the strong magnetoelastic interactions in these compounds, is very satisfactory.
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Paul S, Sanyal B, Ghosh S. Magnetic properties of Mn2NiSn shape memory alloy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:236005. [PMID: 23696265 DOI: 10.1088/0953-8984/25/23/236005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this paper, we present the magnetic properties of the inverse Heusler Mn2NiSn alloy computed by ab initio density functional theory (DFT) calculations in order to understand the large magnetic moments observed in experiments in contrast to smaller values obtained in previous ab initio calculations. Our results show that the magnetization in this system is quite sensitive to volume and atomic ordering in the sublattices. The observed variations in the magnetizations are explained from the features in the electronic structures of the Mn d-bands. We conclude that the symmetry of lattice sites and the alloying with Ni atoms are responsible for a high magnetic moment for a range of volumes. This opens a possible route to realize a large magnetization, a requirement for shape memory properties in magnetic alloys, in similar systems with an inverse Heusler structure.
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Affiliation(s)
- Souvik Paul
- Department of Physics, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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Mössbauer Spectroscopy Studies on Magnetic Properties for 57Fe-substituted Ni-Mn-Sn Metamagnetic Shape Memory Alloys. METALS 2013. [DOI: 10.3390/met3020225] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Singh S, Nayak J, Rai A, Rajput P, Hill AH, Barman SR, Pandey D. (3 + 1)D superspace description of the incommensurate modulation in the premartensite phase of Ni2MnGa: a high resolution synchrotron x-ray powder diffraction study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:212203. [PMID: 23656722 DOI: 10.1088/0953-8984/25/21/212203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Le Bail and Rietveld analysis of high resolution synchrotron x-ray powder diffraction (SXRPD) data shows unambiguous signatures of the failure of the commensurate 3M modulation model. Using (3 + 1) dimensional superspace group formalism, we have not only confirmed the incommensurate modulation in the premartensite phase with a modulation wavevector of q = 0.337 61(5)c* but also determined the superspace group (Immm(00γ)s00), atomic positions and amplitude of modulations for the incommensurate premartensite phase of Ni2MnGa for the first time. Our results may have important implications in the understanding of the martensitic transition and hence the magnetic field induced strains.
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Affiliation(s)
- Sanjay Singh
- UGC-DAE Consortium for Scientific Research, Indore, India
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Magneto-Structural Properties of Ni2MnGa Ferromagnetic Shape Memory Alloy in Magnetic Fields. METALS 2013. [DOI: 10.3390/met3020202] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Roy SB. First order magneto-structural phase transition and associated multi-functional properties in magnetic solids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:183201. [PMID: 23598463 DOI: 10.1088/0953-8984/25/18/183201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We show that the first order magneto-structural phase transitions observed in various classes of magnetic solids are often accompanied by useful multi-functional properties, namely giant magneto-resistance, magneto-caloric effect and magneto-striction. We highlight various characteristic features associated with a disorder influenced first order phase transition namely supercooling, superheating, phase-coexistence and metastability, in several magnetic materials and discuss how a proper understanding of the transition process can help in fine tuning of the accompanied functional properties. Magneto-elastic coupling is a key element in this first order phase transition, and methods need to be explored for maximizing the contributions from both the lattice and the magnetic degree of freedom while simultaneously minimizing the thermomagnetic hysteresis loss. An analogy is also drawn with the first order phase transition observed in dielectric materials and vortex matter of type-II superconductors.
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Affiliation(s)
- Sindhunil Barman Roy
- Magnetic and Superconducting Materials Section, Materials and Advanced Accelerator Sciences Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, India.
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Sathe VG, Dubey A, Banik S, Barman SR, Olivi L. An x-ray absorption spectroscopy study of Ni-Mn-Ga shape memory alloys. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:046001. [PMID: 23238326 DOI: 10.1088/0953-8984/25/4/046001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The austenite to martensite phase transition in Ni-Mn-Ga ferromagnetic shape memory alloys was studied by extended x-ray absorption fine structure (EXAFS) and x-ray absorption near-edge structure (XANES) spectroscopy. The spectra at all the three elements', namely, Mn, Ga and Ni, K-edges in several Ni-Mn-Ga samples (with both Ni and Mn excess) were analyzed at room temperature and low temperatures. The EXAFS analysis suggested a displacement of Mn and Ga atoms in opposite direction with respect to the Ni atoms when the compound transforms from the austenite phase to the martensite phase. The first coordination distances around the Mn and Ga atoms remained undisturbed on transition, while the second and subsequent shells showed dramatic changes indicating the presence of a modulated structure. The Mn rich compounds showed the presence of antisite disorder of Mn and Ga. The XANES results showed remarkable changes in the unoccupied partial density of states corresponding to Mn and Ni, while the electronic structure of Ga remained unperturbed across the martensite transition. The post-edge features in the Mn K-edge XANES spectra changed from a double peak like structure to a flat peak like structure upon phase transition. The study establishes strong correlation between the crystal structure and the unoccupied electronic structure in these shape memory alloys.
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Affiliation(s)
- V G Sathe
- UGC-DAE Consortium for Scientific Research, Khandwa Road, Indore, 452001, India.
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Graf T, Winterlik J, Müchler L, Fecher GH, Felser C, Parkin SS. Magnetic Heusler Compounds. HANDBOOK OF MAGNETIC MATERIALS 2013. [DOI: 10.1016/b978-0-444-59593-5.00001-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Pramanick A, Lauter V, Wang XL, An K, Ambaye H, Goyette Jr RJ, Yi J, Gai Z, Stoica AD. Polarized neutron diffraction at a spallation source for magnetic studies. J Appl Crystallogr 2012. [DOI: 10.1107/s0021889812034474] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The availability of high-power spallation neutron sources, along with advances in the development of coupled moderators and neutron polarizers, has made it possible to use polarized neutrons on time-of-flight diffractometers forin situstudies of phenomena contributing to field-induced magnetization of a material. Different electronic and structural phenomena that contribute to the overall magnetization of a material can be studied and clearly identified with polarized neutron diffraction measurements. This article reports the first results from polarized neutron diffraction experiments on a time-of-flight instrument at a spallation source. Magnetic field-induced rotation of electron spins in an Ni–Mn–Ga single crystal was measured with polarized neutron diffraction at the MAGICS reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. The difference in intensities measured with spin-up and spin-down polarized neutrons is proportional to the field-induced magnetization of the crystal. The polarized neutron measurements indicate that the magnetic form factor for the 3delectrons of Mn in Ni–Mn–Ga is lower than the value reported earlier for an ideal spherical symmetry of electronic distribution. Future experiments for studying field-induced magnetization in materials following the current methodology are outlined.
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Brown PJ, Gandy AP, Kainuma R, Kanomata T, Neumann KU, Oikawa K, Ouladdiaf B, Sheikh A, Ziebeck KRA. The field and temperature dependence of the magnetic and structural properties of the shape memory compound Ni(1.84)Mn(1.64)In(0.52). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:456004. [PMID: 22037587 DOI: 10.1088/0953-8984/23/45/456004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Magnetization and high resolution neutron powder diffraction measurements have been made on the magnetic shape memory alloy Ni(1.84)Mn(1.64)In(0.52). The compound undergoes a broad structural phase transition, which on heating starts at ∼150 K and finishes at ∼215 K. On cooling there is a ∼20 K hysteresis. The high temperature parent phase is cubic (a = 5.988 Å) with the L2(1) structure in which the excess Mn atoms occupy the vacancies on the Ni and In sites. The magnetic moment is located mainly on the Mn atoms with the same magnitude on both the 4a (Mn) and 4b (In) sites. The low temperature martensite is monoclinic with parameters a = 4.405(2), b = 5.553(2), c = 12.950(2) Å, β = 86.47(10)° and space group P2/m. The magnetic properties of the martensitic phase are complex and indicate metamagnetic behaviour.
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Affiliation(s)
- P J Brown
- Department of Physics, Loughborough University, LE11 3TU, UK. Institut Laue Langevin, BP 156, 38042 Grenoble, France
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