近日，中国科学院物理研究所陈根富及其研究小组取得一项新进展。经过不懈努力，他们揭示Mn₃Sn₂单晶的高度各向异性磁性和近各向同性磁热效应。相关研究成果已于2023年12月20日在国际知名学术期刊《中国物理快报》上发表。

本文首次介绍了使用Bi助熔剂制备Mn3_Sn₂单晶的方法。研究人员针对所得晶体的三个主要晶体学方向，深入研究了其各向异性磁化率性能和磁热效应。在低磁场环境下，他们观察到了明显的磁化率各向异性和多场致变磁跃迁现象。值得注意的是，磁热效应表现出近乎各向同性的特性，并且比多晶材料更为显著。

当沿c轴方向施加磁场变化μ₀ΔH=5T时，在T_C1附近磁熵变化达到最大值ΔSM=4.01J/kg/K，其对应的制冷剂容量为1750mJ/cm³。考虑到其更宽的冷却温度范围(~80K)，这项研究结果表明，Mn₃Sn₂单晶是一种极具潜力的低温主动磁制冷候选工作材料。

据悉，Mn3Sn2被认为是一种理想的磁致冷材料。它经历了两次连续的铁磁跃迁（TC1=262K和TC2=227K）和一次反铁磁跃迁（TN=192K）。

附：英文原文

Title: Highly Anisotropic Magnetism and Nearly Isotropic Magnetocaloric Effect inMn₃Sn₂ Single Crystals

Author:

Issue&Volume: 2023-12-20

Abstract: Mn3Sn2 has been proposed as an ideal material for magnetic refrigeration. It undergoes two successive ferromagnetic transitions (T_C1=262K and T_C2=227K) and one antiferromagnetic transition (T_N=192K). Herein we report, for the first time, the preparation of single crystals of Mn₃Sn₂ from Bi flux. The resultant anisotropic magnetic properties and magnetocaloric effect are investigated along the three principal crystallographic directions of the crystal. Significant anisotropy of magnetic susceptibility and multiple field-induced metamagnetic transitions were found at low fields, whereas the magnetocaloric effect was found to be almost isotropic and larger than that of the polycrystalline one. The maximum magnetic entropy change amounts to -ΔS_M=4.01J/kg/K near T_C1 under a magnetic field change of μ₀ΔH=5T along the c-axis, with the corresponding refrigerant capacity of 1750mJ/cm³. Combined with a much wider cooling temperature span (～80K), our results demonstrate Mn₃Sn₂ single crystal to be an attractive candidate working material for active magnetic refrigeration at low temperatures.

DOI: 10.1088/0256-307X/40/12/127501

Source: https://cpl.iphy.ac.cn/10.1088/0256-307X/40/12/127501