Institute of Magnetism NASU and MESU, Kyiv, 03142, Ukraine.
Faculty of Physics, University of Vienna, 1090, Vienna, Austria.
Sci Rep. 2023 Jun 20;13(1):10004. doi: 10.1038/s41598-023-37272-0.
A specific heat of the magnetic solid exhibiting AFM-FM phase transition is computed using the Landau-type theory of phase transitions. The experimentally observed dependence of the specific heat value on the external magnetic field is modelled. It is shown, that this dependence has strong influence on the giant magnetocaloric effect (MCE), which is inherent to the solids exhibiting the phase transitions accompanied by the strong change of magnetization value: the disregard of this dependence leads to the noticeable overestimation of adiabatic temperature change, which is the practically important characteristic of MCE. The temperature change characterizing the giant MCE observed in Fe-Rh alloys is computed. The reasonable agreement between the available experimental data and obtained theoretical results is demonstrated.
采用相变的 Landau 型理论，计算了具有反铁磁-铁磁相变的磁性固体的比热。模拟了实验观测到的比热值对外磁场的依赖关系。结果表明，这种依赖性对巨磁热效应（MCE）有很大的影响，巨磁热效应是在伴随磁化强度值发生强烈变化的相变中固有的：忽略这种依赖性会导致对绝热温度变化的明显高估，这是 MCE 的一个实际重要特征。计算了在 Fe-Rh 合金中观察到的巨 MCE 的温度变化。展示了可用的实验数据和获得的理论结果之间的合理一致性。
