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Litzbarski LS, Klimczuk T, Winiarski MJ. Ho 2Pd 1.3Ge 2.7 - a ternary AlB 2-type cluster glass system. RSC Adv 2021; 11:25187-25193. [PMID: 35478914 PMCID: PMC9036949 DOI: 10.1039/d1ra04422b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 07/11/2021] [Indexed: 11/24/2022] Open
Abstract
We report a successful synthesis of a ternary AlB2-type intermetallic compound. The phase purity was obtained by fine-tuning the Pd : Ge ratio out of the idealized 1 : 3. Attempts to synthesize an Er analogue were not successful. We discuss the instability of the Er analogue based on the atomic size ratio and also suggest that the increased stability of Ho2Pd1+xGe3−x in the Pd-rich range likely stems from a combination of atomic size ratio, electronic, and entropic factors. The new Ho2Pd1.3Ge2.7 compound is found to exhibit cluster glass behavior with a freezing temperature of T ≈ 2.3 K. A ternary AlB2-type cluster glass system was studied. We discuss the factors responsible for stability of its simple hexagonal structure.![]()
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Affiliation(s)
- Leszek S Litzbarski
- Faculty of Applied Physics and Mathematics, Advanced Materials Center, Gdansk University of Technology Narutowicza 11/12 80-232 Gdansk Poland
| | - Tomasz Klimczuk
- Faculty of Applied Physics and Mathematics, Advanced Materials Center, Gdansk University of Technology Narutowicza 11/12 80-232 Gdansk Poland
| | - Michał J Winiarski
- Faculty of Applied Physics and Mathematics, Advanced Materials Center, Gdansk University of Technology Narutowicza 11/12 80-232 Gdansk Poland
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Kundu M, Pakhira S, Choudhary R, Paudyal D, Lakshminarasimhan N, Avdeev M, Cottrell S, Adroja D, Ranganathan R, Mazumdar C. Complex magnetic properties associated with competing local and itinerant magnetism in [Formula: see text]. Sci Rep 2021; 11:13245. [PMID: 34168172 PMCID: PMC8225917 DOI: 10.1038/s41598-021-90751-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 05/12/2021] [Indexed: 12/03/2022] Open
Abstract
Ternary intermetallic compound [Formula: see text] has been synthesized in single phase and characterized by x-ray diffraction, scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDX) analysis, magnetization, heat capacity, neutron diffraction and muon spin rotation/relaxation ([Formula: see text]SR) measurements. The polycrystalline compound was synthesized in single phase by introducing necessary vacancies in Co/Si sites. Magnetic, heat capacity, and zero-field neutron diffraction studies reveal that the system undergoes magnetic transition below [Formula: see text]4 K. Neutron diffraction measurement further reveals that the magnetic ordering is antiferromagnetic in nature with an weak ordered moment. The high temperature magnetic phase has been attributed to glassy in nature consisting of ferromagnetic clusters of itinerant (3d) Co moments as evident by the development of internal field in zero-field [Formula: see text]SR below 50 K. The density-functional theory (DFT) calculations suggest that the low temperature magnetic transition is associated with antiferromagnetic coupling between Pr 4f and Co 3d spins. Pr moments show spin fluctuation along with unconventional orbital moment quenching due to crystal field. The evolution of the symmetry and the crystalline electric field environment of Pr-ions are also studied and compared theoretically between the elemental Pr and when it is coupled with other elements such as Co. The localized moment of Pr 4f and itinerant moment of Co 3d compete with each other below [Formula: see text]20 K resulting in an unusual temperature dependence of magnetic coercivity in the system.
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Affiliation(s)
- Mily Kundu
- Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064 India
| | - Santanu Pakhira
- Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064 India
- Ames Laboratory-USDOE, Iowa State University, Ames, Iowa 50011 USA
| | - Renu Choudhary
- Ames Laboratory-USDOE, Iowa State University, Ames, Iowa 50011 USA
| | - Durga Paudyal
- Ames Laboratory-USDOE, Iowa State University, Ames, Iowa 50011 USA
- Electrical and Computer Engineering Department, Iowa State University, Ames, Iowa 50011 USA
| | - N. Lakshminarasimhan
- Electro-organic and Materials Electrochemistry Division, CSIR-Central Electrochemical Research Institute, Karaikudi, 630 003 India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002 India
| | - Maxim Avdeev
- Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Road, Lucas Heights, NSW 2234 Australia
- School of Chemistry, The University of Sydney, Sydney, NSW 2006 Australia
| | - Stephen Cottrell
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX UK
| | - Devashibhai Adroja
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX UK
- Highly Correlated Matter Research Group, Physics Department, University of Johannesburg, PO Box 524, Auckland Park, 2006 South Africa
| | - R. Ranganathan
- Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064 India
| | - Chandan Mazumdar
- Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, 700064 India
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Pakhira S, Kundu M, Ranganathan R, Mazumdar C. Studies on magnetocaloric effect of Tb 2Ni 0.90Si 2.94 compound. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 33:095804. [PMID: 33237881 DOI: 10.1088/1361-648x/abcdb2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A comparative study has been carried out on the magnetocaloric properties of as-cast and annealed Tb2Ni0.90Si2.94 intermetallic compound. While the as-cast material exhibits ferromagnetic cluster-glass behaviour below 9.9 K coexisting with antiferromagnetic (AFM) interaction, the annealed system shows AFM ordering below 13.5 K and spin freezing occurs below 4 K. The compound exhibits moderate magnetocaloric performance with maximum isothermal entropy changes (-ΔS M) 8.8 and 10.9 J kg-1 K-1, relative cooling power (RCP) 306 and 365 J kg-1, along with adiabatic temperature change (ΔT ad) 5.5 and 8.15 K for 70 kOe magnetic field change in as-cast and annealed forms, respectively. The estimated magnetic entropy change is found to be larger for annealed sample in comparison to that of as-cast analogue. However, the full width at half maxima (FWHM) of -ΔS M(T) behaviour is larger in as-cast compound due to the presence of inherent structural disorder which reduces with thermal annealing. A positive isothermal entropy change (-ΔS M) and adiabatic temperature change (ΔT ad) is observed for the as-cast compound in the measured field and temperature region. In contrast, the annealed system exhibits inverse magnetocaloric effect in the low field and temperature region where AFM interactions dominate. Magnetocaloric effect (MCE) is used as a tool to establish a subtle correlation between the observed magnetocaloric effect and the reported magnetic properties of the system.
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Affiliation(s)
- Santanu Pakhira
- Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India
- Ames Laboratory, Ames, Iowa 50011, United States of America
| | - Mily Kundu
- Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India
| | - R Ranganathan
- Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India
| | - Chandan Mazumdar
- Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India
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Unusual bidirectional frequency dependence of dynamical susceptibility in hexagonal intermetallic Pr 2Ni 0.95Si 2.95. Sci Rep 2018; 8:14870. [PMID: 30291264 PMCID: PMC6173772 DOI: 10.1038/s41598-018-32740-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 08/14/2018] [Indexed: 11/16/2022] Open
Abstract
In this study, the synthesis of a novel ternary intermetallic compound Pr2Ni0.95Si2.95 forming in single phase only by deliberately introducing vacancies in Ni/Si site is reported. The detailed studies on dc magnetization, heat capacity, ac magnetization & associated dynamical scaling, different types of non-equilibrium dynamical behaviour, viz., magnetic relaxation behaviour as a function of wait time and temperature, aging phenomena, and magnetic memory effect firmly establish that the compound exhibits spin freezing behaviour below 3.3 K (Tf). However, below Tf, temperature dependence of ac susceptibility data exhibit an additional peak that shows reverse frequency dependence to that generally observed in a glassy system. The unusual bidirectional frequency dependence in a single magnetic system is of significant interest and rarely reported in literature. Competing exchange interaction arising from c/a ~ 1 and crystallographic randomness driven magnetic phase separation has been argued to be responsible for such observation. The reverse frequency shift of the low temperature peak has been described on the basis of a simple phenomenological model proposed in this work.
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Pakhira S, Kundu AK, Mazumdar C, Ranganathan R. Role of random magnetic anisotropy on the valence, magnetocaloric and resistivity properties in a hexagonal Sm 2Ni 0.87Si 2.87 compound. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:215601. [PMID: 29623904 DOI: 10.1088/1361-648x/aabc22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this work, we report the effect of random magnetic anisotropy (RMA) on the valence, magnetocaloric and resistivity properties in a glassy intermetallic material Sm2Ni0.87Si2.87. On the basis of detailed studies on the valence band and core level electronic structure, we have established that both the Sm3+ and Sm2+ ions are present in the system, suggesting the compound to be of mixed valence in nature. The significant observation of positive magnetic entropy change in zero-field cooled measurement has been argued due to the presence of RMA that develops due to local electronic environmental variations between the rare-earth ions in the system. The quantum interference effect caused by the elastic electron-electron interaction is responsible for the resistivity upturn at low-temperature for this disordered metallic conductor.
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Affiliation(s)
- Santanu Pakhira
- Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India
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