Magnetocaloric effect in molecular magnet
| Autor: | Piotr Zieliński, Piotr Konieczny, Tadeusz Wasiutyński, Dawid Pinkowicz, Barbara Sieklucka, Yuji Miyazaki, Akira Inaba, Robert Pełka |
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| Rok vydání: | 2014 |
| Předmět: |
Phase transition
Materials science Condensed matter physics Transition temperature Space group Calorimetry Crystal structure Pyrazole Condensed Matter Physics Electronic Optical and Magnetic Materials chemistry.chemical_compound Tetragonal crystal system Crystallography chemistry Magnetic refrigeration |
| Zdroj: | Journal of Magnetism and Magnetic Materials. 354:359-362 |
| ISSN: | 0304-8853 |
| DOI: | 10.1016/j.jmmm.2013.11.047 |
| Popis: | Magnetocaloric effect in { [ Fe ( pyrazole ) 4 ] 2 [ Nb ( Cn ) 8 ] · 4 H 2 O } n molecular magnet is reported. It crystallizes in tetragonal I41/a space group. The compound exhibits a phase transition to a long range magnetically ordered state at T c ≈ 8.3 K . The magnetic entropy change Δ S M as well as the adiabatic temperature change Δ T ad due to applied field change μ 0 Δ H = 0.1 , 0.2, 0.5, 1, 2, 5, 9 T as a function of temperature have been determined by the relaxation calorimetry measurements. The maximum value of Δ S M for μ 0 Δ H = 5 T is 4.9 J mol−1 K−1 (4.8 J kg−1 K−1) at 10.3 K. The corresponding maximum value of Δ T ad is 2.0 K at 8.9 K. The temperature dependence of the exponent n characterizing the field dependence of Δ S M has been estimated. It attains the value of 0.64 at the transition temperature, which is consistent with the 3D Heisenberg universality class. |
| Databáze: | OpenAIRE |
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