Abstract

The magnetocaloric effect in nanosystems based on exchange-coupled ferromagnets with different Curie temperatures is calculated within the mean-field theory. Good agreement between the results of the mean-field theory and the Landau theory, valid near the critical phase transition temperature, is demonstrated for a flat-layered Fe/Gd/Fe structure. We show that a high magnetic cooling efficiency in this system is attainable in principle and prove the validity of the Maxwell relation, enabling an experimental verification of the predictions made. The theory developed for flat-layered structures is generalized to a granular medium.

中文翻译：

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不同居里温度的铁磁体在纳米系统中的磁热效应

摘要

在平均场理论下，计算了基于具有不同居里温度的交换耦合铁磁体的纳米系统中的磁热效应。对于平坦的Fe / Gd / Fe结构，证明了在临界相变温度附近有效的平均场理论和Landau理论之间的良好一致性。我们证明，从原理上讲，该系统具有较高的磁冷却效率，并证明了麦克斯韦关系的有效性，从而可以对所做出的预测进行实验验证。为平层结构开发的理论被推广到粒状介质。