L'vov Victor A, Salyuk Olga, Kosogor Anna
V.G. Baryakhtar Institute of Magnetism of the NAS of Ukraine, Kyiv, Ukraine.
National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", Kyiv, Ukraine.
Sci Rep. 2025 Aug 23;15(1):31002. doi: 10.1038/s41598-025-15896-8.
A thermodynamic analysis of the magnetic, caloric and magnetocaloric properties of the ferromagnets undergoing the structural phase transitions (SPTs) near the Curie temperature has been carried out taking into account the effect of SPT on the energy of magnetic subsystem of ferromagnet. A special emphasis has been placed on the account of minimum conditions for Gibbs free energy and the modification of magnetic Maxwell relations with consideration of the effect of SPT on the magnetic energy. The computations, based on the commonly used equations for the energy and entropy of the magnetic subsystem of ferromagnet, discovered and estimated quantitatively a drastic dependence of magnetic heat capacity and magnetic-field-induced temperature change on the difference between the SPT temperature and Curie point. The performed theoretical analysis is aimed to motivate the systematic experimental research of magnetic and magnetocaloric materials undergoing the SPT at temperatures intentionally tuned close to the Curie point.
考虑到结构相变对铁磁体磁子系统能量的影响，对居里温度附近发生结构相变（SPT）的铁磁体的磁性、热性质和磁热性质进行了热力学分析。特别强调了吉布斯自由能的最小条件以及考虑结构相变对磁能的影响时磁麦克斯韦关系的修正。基于铁磁体磁子系统能量和熵的常用方程进行的计算，定量地发现并估计了磁热容量和磁场诱导温度变化对结构相变温度与居里点之差的强烈依赖性。所进行的理论分析旨在推动对在有意调谐到接近居里点的温度下发生结构相变的磁性和磁热材料进行系统的实验研究。
