Insight into anisotropic magnetocaloric effect of CrI3
Insight into anisotropic magnetocaloric effect of CrI3
复制标题
深入了解 CrI3 的各向异性磁热效应
DOI：
10.1016/j.actamat.2022.117851
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发表时间：
2022
期刊：
影响因子：
9.4
通讯作者：
Oguchi Tamio
中科院分区：
文献类型：
--
作者：
Tran Hung Ba;Momida Hiroyoshi;Matsushita Yu-ichiro;Shirai Koun;Oguchi Tamio
CrI 3被认为是自旋电子学器件和数据存储的一种有希望的候选材料。我们推导出海森堡哈密顿量CrI 3密度泛函计算使用列支敦士登公式。此外，采用Sucksmith-Thompson方法进行了蒙特-卡罗模拟，分析了磁各向异性能对热力学性质的影响。我们的方法成功地再现了负符号的等温磁熵变时，施加磁场沿着硬平面。我们发现，温度依赖性的磁晶各向异性能量是不可忽略的温度略高于居里温度。我们澄清了这种现象的起源归因于各向异性的磁化率和磁化各向异性。易磁化轴和硬平面的熵变之间的差异与磁各向异性能量的温度依赖性成比例，这意味着各向异性熵项是在易磁化轴以外的特定方向磁化时自由能差的温度依赖性的主要来源。我们还研究了磁化率，可用于表征的情况下，硬平面的熵变的负符号。在低温和低磁场下，磁晶各向异性能和外磁场的竞争导致磁化强度波动时的高磁化率。同时，当沿难磁化轴沿着施加足够的磁场时，各向异性能被抑制，并且磁化被完全旋转到外部磁场的方向。
CrI 3 is considered to be a promising candidate for spintronic devices and data storage. We derived the Heisenberg Hamiltonian for CrI 3 from density functional calculations using the Liechtenstein formula. Moreover, the Monte–Carlo simulations with the Sucksmith–Thompson method were performed to analyze the effect of magnetic anisotropy energy on the thermodynamic properties. Our method successfully reproduced the negative sign of isothermal magnetic entropy changes when a magnetic field was applied along the hard plane. We found that the temperature dependence of the magnetocrystalline anisotropy energy is not negligible at temperatures slightly above the Curie temperature. We clarified that the origin of this phenomenon is attributed to anisotropic magnetic susceptibility and magnetization anisotropy. The difference between the entropy change of the easy axis and the hard plane is proportional to the temperature dependence of the magnetic anisotropy energy, implying that the anisotropic entropy term is the main source of the temperature dependence of the free energy difference when magnetizing in a specific direction other than the easy axis. We also investigated the magnetic susceptibility that can be used for the characterization of the negative sign of the entropy change in the case of a hard plane. The competition of the magnetocrystalline anisotropy energy and external magnetic field at a low temperature and low magnetic field causes a high magnetic susceptibility as the magnetization fluctuates. Meanwhile, the anisotropy energy is suppressed as a sufficient magnetic field is applied along the hard axis, and the magnetization is fully rotated to the direction of the external magnetic field.