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Abstract
The magnetocaloriceffect is considered as an energy-efficient and environmentally friendly technique which can take cooling technology to the next level. Apart from its commercial application at room temperature, magnetic refrigeration is an up-and-coming solution for the cryogenic regime, especially as an alternative to He3 systems. Molecular magnets reveal advantageous features for ultra-low cooling which are competitive with intermetallic and lanthanide alloys. Here, we present a guide to the current status of magnetocaloric effect research of molecular magnets with a theoretical background focused on the inverse magnetocaloric effect and an overview of recent results and developments, including the rotating magnetocaloric effect.
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Affiliation(s)
- Piotr Konieczny
- Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Kraków, Poland.
| | - Wojciech Sas
- Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Kraków, Poland.
| | - Dominik Czernia
- Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Kraków, Poland.
| | | | - Magdalena Fitta
- Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Kraków, Poland.
| | - Robert Pełka
- Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Kraków, Poland.
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2
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Qasem KMA, Khan S, Fitta M, Akhtar MN, AlDamen MA, Shahid M, Saleh HAM, Ahmad M. A new {Cu3-Gd2} cluster as two-in-one functional material with unique topology acting as a refrigerant as well as adsorbent for cationic dye. CrystEngComm 2022. [DOI: 10.1039/d2ce00795a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new heterometallic cluster system, [Cu3Gd2(H3btp)2(OAc)6]3H2O {Cu3-Gd2} is designed by employing 1,3-Bis(tris(hydroxymethyl)methylamino)propane (H6btp) as a ligand. The cluster is characterized by FTIR, TGA, PXRD, SCXRD and topological analyses. The crystallography...
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3
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Episcopo N, Chang PH, Heitmann TW, Wangmo K, McKamey Guthrie J, Fitta M, Klein RA, Poudel N, Gofryk K, Zope RR, Brown CM, Nair HS. Magnetic structure, excitations and short-range order in honeycomb Na 2Ni 2TeO 6. J Phys Condens Matter 2021; 33:375803. [PMID: 34171852 DOI: 10.1088/1361-648x/ac0ea6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/25/2021] [Indexed: 06/13/2023]
Abstract
Na2Ni2TeO6has a layered hexagonal structure with a honeycomb lattice constituted by Ni2+and a chiral charge distribution of Na+that resides between the Ni layers. In the present work, the antiferromagnetic (AFM) transition temperature of Na2Ni2TeO6is confirmed atTN≈ 27 K, and further, it is found to be robust up to 8 T magnetic field and 1.2 GPa external pressure; and, without any frequency-dependence. Slight deviations from nominal Na-content (up to 5%) does not seem to influence the magnetic transition temperature,TN. Isothermal magnetization curves remain almost linear up to 13 T. Our analysis of neutron diffraction data shows that the magnetic structure of Na2Ni2TeO6is faithfully described by a model consisting of two phases described by the commensurate wave vectorsk→c,0.500and0.500.5, with an additional short-range order component incorporated in to the latter phase. Consequently, a zig-zag long-range ordered magnetic phase of Ni2+results in the compound, mixed with a short-range ordered phase, which is supported by our specific heat data. Theoretical computations based on density functional theory predict predominantly in-plane magnetic exchange interactions that conform to aJ1-J2-J3model with a strongJ3term. The computationally predicted parameters lead to a reliable estimate forTNand the experimentally observed zig-zag magnetic structure. A spin wave excitation in Na2Ni2TeO6atE≈ 5 meV atT= 5 K is mapped out through inelastic neutron scattering experiments, which is reproduced by linear spin wave theory calculations using theJvalues from our computations. Our specific heat data and inelastic neutron scattering data strongly indicate the presence of short-range spin correlations, atT>TN, stemming from incipient AFM clusters.
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Affiliation(s)
- Nathan Episcopo
- Department of Physics, 500 W. University Ave, University of Texas at El Paso, TX 79968, United States of America
| | - Po-Hao Chang
- Department of Physics, 500 W. University Ave, University of Texas at El Paso, TX 79968, United States of America
| | - Thomas W Heitmann
- University of Missouri Research Reactor, University of Missouri, Columbia, MO 65211, United States of America
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, United States of America
| | - Kinley Wangmo
- Department of Physics, 500 W. University Ave, University of Texas at El Paso, TX 79968, United States of America
| | - James McKamey Guthrie
- University of Missouri Research Reactor, University of Missouri, Columbia, MO 65211, United States of America
| | - Magdalena Fitta
- Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Kraków, Poland
| | - Ryan A Klein
- Chemistry and Nanoscience Department, National Renewable Energy Laboratory, Golden CO 80401, United States of America
- Center for Neutron Research, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, United States of America
| | - Narayan Poudel
- Idaho National Laboratory, Idaho Falls, ID 83415, United States of America
| | - Krzysztof Gofryk
- Center for Neutron Research, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, United States of America
| | - Rajendra R Zope
- Department of Physics, 500 W. University Ave, University of Texas at El Paso, TX 79968, United States of America
| | - Craig M Brown
- Chemistry and Nanoscience Department, National Renewable Energy Laboratory, Golden CO 80401, United States of America
| | - Harikrishnan S Nair
- Department of Physics, 500 W. University Ave, University of Texas at El Paso, TX 79968, United States of America
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4
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Sas W, Pinkowicz D, Perzanowski M, Fitta M. Magnetic, Structural and Spectroscopic Properties of Iron(II)-Octacyanoniobate(IV) Crystalline Film Obtained by Ion-Exchange Synthesis. Materials (Basel) 2020; 13:ma13133029. [PMID: 32645872 PMCID: PMC7372376 DOI: 10.3390/ma13133029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 11/24/2022]
Abstract
Over recent years, investigations of coordination polymer thin films have been initiated due to their unique properties, which are expected to be strongly enhanced in the thin film form. In this work, a crystalline [FeII(H2O)2]2[NbIV(CN)8]∙4H2O (1) film on a transparent Nafion membrane was obtained, for the first time, via ion-exchange synthesis. The proper film formation and its composition was confirmed with the use of energy dispersive X-ray spectroscopy and infrared spectroscopy, as well as in situ Ultraviolet-Visible (UV-Vis) spectroscopy. The obtained film were also characterized by scanning electron microscopy, X-ray diffraction, and magnetic measurements. The [FeII(H2O)2]2[NbIV(CN)8]∙4H2O film shows a sharp phase transition to a long-range magnetically ordered state at Tc = 40 K. The 1 film is a soft ferromagnet with the coercive field Hc = 1.2 kOe. Compared to the bulk counterpart, a decrease in critical temperature and a significant increase in the coercive field were observed in the films indicating a distinct size effect. The decrease in Tc could also have been related to the possible partial oxidation of FeII ions to FeIII, which could be efficient, due to the large surface of the thin film sample.
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Affiliation(s)
- Wojciech Sas
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, 31-342 Krakow, Poland; (W.S.); (M.P.)
| | - Dawid Pinkowicz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland;
| | - Marcin Perzanowski
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, 31-342 Krakow, Poland; (W.S.); (M.P.)
| | - Magdalena Fitta
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, 31-342 Krakow, Poland; (W.S.); (M.P.)
- Correspondence:
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Hfidhi N, Korb M, Fitta M, Čižmár E, Lang H, Naïli H. Magneto-electronic properties and structural features of unusual bis(μ-aqua) bis(μ-sulfato) bridges in binuclear cobalt-based 4-aminopyridine. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.09.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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6
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Fitta M, Pełka R, Sas W, Pinkowicz D, Sieklucka B. Dinuclear molecular magnets with unblocked magnetic connectivity: magnetocaloric effect. RSC Adv 2018; 8:14640-14645. [PMID: 35540743 PMCID: PMC9079940 DOI: 10.1039/c8ra01609g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 04/12/2018] [Indexed: 11/21/2022] Open
Abstract
A detailed study of the magnetocaloric effect in two isostructural bimetallic compounds {[MII(H2O)2]2[NbIV(CN)8]·4H2O}n (M = Mn, Fe) is presented. The substances show sharp phase transitions to the long-range magnetically ordered state with ferromagnetic coupling between M and Nb sublattices in the case of the Fe-based sample (FeNb, Tc = 43 K) and antiferromagnetic coupling for the Mn-based sample (MnNb, Tc = 50 K). The magnetic entropy change was found to reach 5.07 J mol−1 K−1 (9.09 J kg−1 K−1) for MnNb and 4.82 J mol−1 K−1 (8.65 J kg−1 K−1) for FeNb under the applied magnetic field change of 5 T. Isothermal entropy changes corresponding to different field changes are demonstrated to collapse on a single master curve, which confirms the magnetic transitions in FeNb and MnNb to be of the second order. The results obtained for FeNb and MnNb are discussed in the context of MCE tunability by un/blocking of magnetic connectivity through dis/reconnection of spatially extended ligands. The study of magnetocaloric effect in two related bimetallic cyanide-bridged molecular magnets: {[M (H2O)2]2[Nb (CN)8]·4H2O}n (M = Mn, Fe) is presented.![]()
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Affiliation(s)
- Magdalena Fitta
- Institute of Nuclear Physics Polish Academy of Sciences
- 31-342 Kraków
- Poland
| | - Robert Pełka
- Institute of Nuclear Physics Polish Academy of Sciences
- 31-342 Kraków
- Poland
| | - Wojciech Sas
- Institute of Nuclear Physics Polish Academy of Sciences
- 31-342 Kraków
- Poland
- AGH University of Science and Technology
- Faculty of Physics and Applied Computer Science
| | - Dawid Pinkowicz
- Faculty of Chemistry
- Jagiellonian University
- 30-060 Kraków
- Poland
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7
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Ghosh S, Hari N, Pinkowicz D, Fitta M, Mohanta S. Syntheses, crystal structures and magnetic properties of a series of ZnII2LnIII2 compounds (Ln = Gd, Tb, Dy, Ho and Er): contrasting structural and magnetic features. NEW J CHEM 2018. [DOI: 10.1039/c8nj02532k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the five ZnII2LnIII2 compounds – (i) the TbIII and ErIII analogues show slow relaxation of the magnetization, while the HoIII system and, surprisingly, the DyIII analogue don’t; (ii) the GdIII system shows the MCE; and (iii) interestingly, the Ln–O bond length increases with the increase of atomic number.
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Affiliation(s)
- Sagar Ghosh
- Department of Chemistry
- University of Calcutta
- Kolkata 700 009
- India
| | - Nairita Hari
- Department of Chemistry
- University of Calcutta
- Kolkata 700 009
- India
| | - Dawid Pinkowicz
- Faculty of Chemistry
- Jagiellonian University
- 30-387 Kraków
- Poland
| | - Magdalena Fitta
- Institute of Nuclear Physics
- Polish Academy of Sciences
- 31-342 Krakow
- Poland
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8
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Hfidhi N, Kammoun O, Pelka R, Fitta M, Naïli H. Structure features, thermal analysis, model and experiment magnetic behavior of tetranuclear oxo and sulfato bridged copper (II) aggregate. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.09.054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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9
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Fitta M, Szuwarzyński M, Czaja P, Lewińska G, Bałanda M. Front Cover: The Magnetocaloric Effect in the Thin Film of a Prussian Blue Analogue (Eur. J. Inorg. Chem. 41/2017). Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201701229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Magdalena Fitta
- Department of Magnetic Materials and Nanostructures Institute of Nuclear Physics Polish Academy of Sciences 31‐342 Krakow Poland
| | - Michał Szuwarzyński
- Faculty of Chemistry Jagiellonian University 30‐060 Kraków Poland
- Academic Centre for Materials and Nanotechnology AGH University of Science and Technology 30‐059 Kraków Poland
| | - Paweł Czaja
- Institute of Metallurgy and Materials Science Polish Academy of Sciences 30‐059 Kraków Poland
| | - Gabriela Lewińska
- Institute of Physics Cracow University of Technology 30‐084 Kraków Poland
| | - Maria Bałanda
- Department of Magnetic Materials and Nanostructures Institute of Nuclear Physics Polish Academy of Sciences 31‐342 Krakow Poland
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10
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Fitta M, Szuwarzyński M, Czaja P, Lewińska G, Bałanda M. The Magnetocaloric Effect in the Thin Film of a Prussian Blue Analogue. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201701230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Magdalena Fitta
- Department of Magnetic Materials and Nanostructures Institute of Nuclear Physics Polish Academy of Sciences 31‐342 Krakow Poland
| | - Michał Szuwarzyński
- Faculty of Chemistry Jagiellonian University 30‐060 Kraków Poland
- Academic Centre for Materials and Nanotechnology AGH University of Science and Technology 30‐059 Kraków Poland
| | - Paweł Czaja
- Institute of Metallurgy and Materials Science Polish Academy of Sciences 30‐059 Kraków Poland
| | - Gabriela Lewińska
- Institute of Physics Cracow University of Technology 30‐084 Kraków Poland
| | - Maria Bałanda
- Department of Magnetic Materials and Nanostructures Institute of Nuclear Physics Polish Academy of Sciences 31‐342 Krakow Poland
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11
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Fitta M, Szuwarzyński M, Czaja P, Lewińska G, Bałanda M. The Magnetocaloric Effect in the Thin Film of a Prussian Blue Analogue. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Magdalena Fitta
- Department of Magnetic Materials and Nanostructures Institute of Nuclear Physics Polish Academy of Sciences 31‐342 Krakow Poland
| | - Michał Szuwarzyński
- Faculty of Chemistry Jagiellonian University 30‐060 Kraków Poland
- Academic Centre for Materials and Nanotechnology AGH University of Science and Technology 30‐059 Kraków Poland
| | - Paweł Czaja
- Institute of Metallurgy and Materials Science Polish Academy of Sciences 30‐059 Kraków Poland
| | - Gabriela Lewińska
- Institute of Physics Cracow University of Technology 30‐084 Kraków Poland
| | - Maria Bałanda
- Department of Magnetic Materials and Nanostructures Institute of Nuclear Physics Polish Academy of Sciences 31‐342 Krakow Poland
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12
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Fitta M, Czaja P, Krupiński M, Lewińska G, Szuwarzyński M, Bałanda M. Magnetic Properties of Bilayer Thin Film Composed of Hard and Soft Ferromagnetic Prussian Blue Analogues. ChemistrySelect 2017. [DOI: 10.1002/slct.201701116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Magdalena Fitta
- Department of Magnetic Materials and Nanostructures; Institute of Nuclear Physics Polish Academy of Sciences; PL-31342 Krakow Poland
| | - Paweł Czaja
- Institute of Metallurgy and Materials Science Polish Academy of Sciences; 30-059 Kraków Poland
| | - Michał Krupiński
- Department of Magnetic Materials and Nanostructures; Institute of Nuclear Physics Polish Academy of Sciences; PL-31342 Krakow Poland
| | - Gabriela Lewińska
- Institute of Physics; Cracow University of Technology; 30-084 Kraków Poland
| | - Michał Szuwarzyński
- Faculty of Chemistry; Jagiellonian University; 30-060 Kraków Poland
- AGH University of Science and Technology; Academic Centre for Materials and Nanotechnology; 30-059 Kraków Poland
| | - Maria Bałanda
- Department of Magnetic Materials and Nanostructures; Institute of Nuclear Physics Polish Academy of Sciences; PL-31342 Krakow Poland
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Arczyński M, Rams M, Stanek J, Fitta M, Sieklucka B, Dunbar KR, Pinkowicz D. A Family of Octahedral Magnetic Molecules Based on [NbIV(CN)8]4–. Inorg Chem 2017; 56:4021-4027. [DOI: 10.1021/acs.inorgchem.6b03134] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mirosław Arczyński
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland
| | - Michał Rams
- Marian
Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza
11, 30-348 Kraków, Poland
| | - Jan Stanek
- Marian
Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza
11, 30-348 Kraków, Poland
| | - Magdalena Fitta
- Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland
| | - Barbara Sieklucka
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland
| | - Kim R. Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States
| | - Dawid Pinkowicz
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States
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14
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Matoga D, Roztocki K, Wilke M, Emmerling F, Oszajca M, Fitta M, Bałanda M. Crystalline bilayers unzipped and rezipped: solid-state reaction cycle of a metal–organic framework with triple rearrangement of intralayer bonds. CrystEngComm 2017. [DOI: 10.1039/c7ce00655a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Fitta M, Prima-Garcia H, Czaja P, Korzeniak T, Krupiński M, Wojtyniak M, Bałanda M. Magnetic and magneto-optical properties of nickel hexacyanoferrate/chromate thin films. RSC Adv 2017. [DOI: 10.1039/c6ra25775e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We present thin films obtained by “layer by layer” deposition, where Fe/Cr ratio is controlled by the dipping sequence. The goal of our work is the investigation of material properties evolution induced by the change of its chemical composition.
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Affiliation(s)
- Magdalena Fitta
- Institute of Nuclear Physics Polish Academy of Sciences
- PL-31342 Krakow
- Poland
| | - Helena Prima-Garcia
- Instituto de Ciencia Molecular (ICMol)
- Universitat de València
- 46980-Paterna
- Spain
| | - Paweł Czaja
- Institute of Metallurgy and Materials Science Polish Academy of Sciences
- Kraków
- Poland
| | | | - Michał Krupiński
- Institute of Nuclear Physics Polish Academy of Sciences
- PL-31342 Krakow
- Poland
| | - Marcin Wojtyniak
- Institute of Physics
- University of Silesia
- Katowice
- Poland
- Silesian Center for Education and Interdisciplinary Research
| | - Maria Bałanda
- Institute of Nuclear Physics Polish Academy of Sciences
- PL-31342 Krakow
- Poland
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16
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Bałanda M, Pełka R, Fitta M, Laskowski Ł, Laskowska M. Relaxation and magnetocaloric effect in the Mn12 molecular nanomagnet incorporated into mesoporous silica: a comparative study. RSC Adv 2016. [DOI: 10.1039/c6ra04063b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Successful incorporation of the Mn12 molecules into silica channels has been attested with AC susceptometry and magnetocaloric effect measurements.
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Affiliation(s)
- Maria Bałanda
- H. Niewodniczański Institute of Nuclear Physics
- Polish Academy of Sciences
- 31-342 Krakow
- Poland
| | - Robert Pełka
- H. Niewodniczański Institute of Nuclear Physics
- Polish Academy of Sciences
- 31-342 Krakow
- Poland
| | - Magdalena Fitta
- H. Niewodniczański Institute of Nuclear Physics
- Polish Academy of Sciences
- 31-342 Krakow
- Poland
| | - Łukasz Laskowski
- Institute of Intelligent Computational Systems
- Częstochowa University of Technology
- 42-200 Częstochowa
- Poland
| | - Magdalena Laskowska
- Institute of Intelligent Computational Systems
- Częstochowa University of Technology
- 42-200 Częstochowa
- Poland
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17
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Radoń M, Rejmak P, Fitta M, Bałanda M, Szklarzewicz J. How can [Mo(IV)(CN)6](2-), an apparently octahedral (d)(2) complex, be diamagnetic? Insights from quantum chemical calculations and magnetic susceptibility measurements. Phys Chem Chem Phys 2015; 17:14890-902. [PMID: 25982910 DOI: 10.1039/c4cp04863f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Quantum chemical calculations are employed to elucidate the origin of a puzzling diamagnetism for a hexacyanomolybdate(IV) anion, [Mo(CN)6](2-), which was previously reported by Szklarzewicz et al. [Inorg. Chem., 2007, 46, 9531-9533]. The diamagnetism is surprising because for the octahedral (d)(2) complex one would rather expect a (paramagnetic) triplet ground state, clearly favored over a (diamagnetic) singlet state by an exchange interaction between two d electrons in the t2g orbitals. Nevertheless, the present calculations reveal that the minimum energy structure of isolated [Mo(CN)6](2-) is not an octahedron, but a trigonal prism; the latter geometry allows maximization of a σ-donation from the cyanides to the electron-deficient Mo(iv) center. Unlike for the octahedron, for the trigonal prism structure the singlet and triplet spin states are close in energy to within a few kcal mol(-1). Although the actual relative energy of the two spin states turns out to be method-dependent, the complete active space calculations (CASPT2; with the appropriate choice of the IPEA shift parameter) can reproduce the singlet ground state, in agreement with the experimentally observed diamagnetism. Moreover, magnetic measurements reveal a slight increase of the magnetic susceptibility with the increase of temperature from 100 to 300 K, suggesting an admixture of a thermally induced paramagnetism (possibly due to Boltzmann population of the low-energy triplet state) on top of the dominant diamagnetism. Our prediction that the geometry of [Mo(CN)6](2-) should significantly deviate from the ideal octahedron, not only in the gas phase, but also in a periodic DFT model of the crystalline phase, as well as the experimentally confirmed diamagnetic properties, does not agree with the previously reported ideal octahedral structure. We suggest that this crystal structure might have been determined incorrectly (e.g., due to overlooked merohedral twinning or superstructure properties) and it should be re-investigated.
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Affiliation(s)
- Mariusz Radoń
- Department of Chemistry, Jagiellonian University in Kraków, Kraków, Poland.
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Mihalik M, Zentková M, Briančin J, Fitta M, Mihalikjr M, Lazúrová J, Vavra M. Magnetic Properties of La 0.8K 0.2MnO 3Nanoparticles. EPJ Web of Conferences 2014. [DOI: 10.1051/epjconf/20147505006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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19
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Fitta M, Bałanda M, Pełka R, Konieczny P, Pinkowicz D, Sieklucka B. Magnetocaloric effect and critical behaviour in Mn2-pyridazine-[Nb(CN)8] molecular compound under press. J Phys Condens Matter 2013; 25:496012. [PMID: 24222387 DOI: 10.1088/0953-8984/25/49/496012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A comprehensive study of magnetocaloric effect (MCE) and critical behaviour in the ferrimagnetic Mn2–pyridazine–[Nb(CN)8] molecular magnet under hydrostatic pressure is reported. The pressure-induced structural changes provoke the strengthening of magnetic interaction between Mn and Nb centres. Consequently, an increase of critical temperature Tc is observed from 43 K for a sample at ambient pressure (A) to 52.5 K for a sample under a pressure of 1.19 GPa (AHP). The magnetocaloric effect was determined by the magnetization measurements. The application of a hydrostatic pressure of 1.19 GPa causes a decrease in the maximum value of magnetic entropy change ΔS, which for AHP is equal to 4.63 J mol−1 K−1 (7.73 J kg−1 K−1) at μ0ΔH = 5 T, while for A it is 5.36 J mol−1 K−1 (8.95 J kg−1 K−1) for the same magnetic field change. The temperature-dependent parameter n obtained for AHP, describing the field dependence of MCE, is consistent with other critical exponents determined from magnetization measurements. The critical exponents allow us to classify AHP to the 3D Heisenberg universality class, similar to the case of the non-pressurized sample.
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Mihalik M, Antoňák M, Csach K, Fitta M, Mihalik M, Vavra M, Zentková M. Exchange Bias Effect in La 1-xAg xMnO 3Nanopowders. EPJ Web of Conferences 2013. [DOI: 10.1051/epjconf/20134015006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Fitta M, Bałanda M, Mihalik M, Pełka R, Pinkowicz D, Sieklucka B, Zentkova M. Magnetocaloric effect in M-pyrazole-[Nb(CN)(8)] (M = Ni, Mn) molecular compounds. J Phys Condens Matter 2012; 24:506002. [PMID: 23174909 DOI: 10.1088/0953-8984/24/50/506002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report a study of magnetocaloric effect (MCE) in cyanido-bridged {[M(II)(pyrazole)(4)](2)[Nb(IV)(CN)(8)]·4H(2)O}(n) molecular compounds where M = Ni, Mn, pyrazole = C(3)H(4)N(2). The substances show a sharp phase transition to a long range magnetically ordered state, with ferromagnetic coupling between M and Nb sublattices in the case of the Ni-based sample 1 (T(c) = 13.4 K) and ferrimagnetic coupling for the Mn-based sample 2 (T(c) = 23.8 K). The magnetic entropy change ΔS due to applied field change ΔH as a function of temperature was determined by the magnetization and heat capacity measurements. The maximum value of ΔS at μ(0)ΔH = 5 T is 6.1 J mol(-1) K(-1) (5.9 J kg(-1) K(-1)) for 1 at T = 14 K and 6.7 J mol(-1) K(-1) (6.5 J kg(-1) K(-1)) for 2 at T = 25 K. MCE data at different applied fields have been presented as one universal curve, which confirms magnetic transitions in 1 and 2 to be of second order. The temperature dependences of the n exponent characterizing the dependence of ΔS on ΔH have been obtained. The n(T(c)) values, consistent with the shape of the magnetization curves, pointed to the 3D Heisenberg behaviour for 2 and some anisotropy, probably of the XY type, for 1. The (H/T(c))(2/3) dependence of the maximum entropy change has been tested in the ferrimagnetic Mn(2)-L-[Nb(CN)(8)] (L = C(3)H(4)N(2), C(4)H(4)N(2)) series.
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Affiliation(s)
- Magdalena Fitta
- Institute of Nuclear Physics, Polish Academy of Sciences, Kraków, Poland.
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Fitta M, Pełka R, Bałanda M, Czapla M, Mihalik M, Pinkowicz D, Sieklucka B, Wasiutyński T, Zentkova M. Magnetocaloric Effect in a Mn2-Pyridazine-[Nb(CN)8] Molecular Magnetic Sponge. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201200374] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Korzeniak T, Pinkowicz D, Nitek W, Bałanda M, Fitta M, Sieklucka B. The role of carboxylate ligands in two novel cyanido-bridged 2D coordination networks CuII–WV and MnII–NbIV. Dalton Trans 2011; 40:12350-7. [DOI: 10.1039/c1dt10800j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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