Evidence of spin reorientation and anharmonicity in kagome ferromagnet Fe3Sn2
Evidence of spin reorientation and anharmonicity in kagome ferromagnet Fe3Sn2
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DOI：
10.1063/5.0063090
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发表时间：
2021-08
影响因子：
4
通讯作者：
P. Wu;Jiuhui Song;Xiaoxiang Yu;Yihao Wang;K. Xia;Bin Hong;L. Zu;Yinchang Du;P. Vallobra-P.-Vallob
中科院分区：
文献类型：
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作者：
P. Wu;Jiuhui Song;Xiaoxiang Yu;Yihao Wang;K. Xia;Bin Hong;L. Zu;Yinchang Du;P. Vallobra-P.-Vallob
近年来在铁磁性金属Fe3Sn2中发现的大量狄拉克费米子和室温费米子由于在拓扑和自旋电子器件中的潜在应用而引起了广泛的关注。由于其中心对称晶格，Fe3Sn2的拓扑自旋织构主要来自于各向异性和交换相互作用之间的竞争。在这篇论文中，我们通过磁化和交流磁化率测量确定了在80 K左右的自旋重定向。从18 ~ 700 K的中子粉末衍射数据揭示了各向异性的演化过程，在较高的温度下，“呼吸”状的kagome结构演变为理想的kagome晶格。同时，高温热容的实验与计算结果的偏差以及拉曼光谱中光学声子模式的软化表明Fe3Sn2中存在非调和声子，这是导致晶格热导率在高温下简并的原因。我们的研究表明，Fe3Sn2在拓扑、自旋电子和热电器件的设计和开发中具有广阔的前景。
Recently discovered massive Dirac fermions and room temperature skyrmions in the ferromagnetic kagome metal Fe3Sn2 have attracted extensive attention due to the potential applications in topological and spintronic devices. Because of its centrosymmetric lattice, the topological spin texture in Fe3Sn2 arises primarily from the competition between anisotropy and exchange interaction. In this Letter, we have identified the spin-reorientation at around 80 K by the magnetization and AC-susceptibility measurements. The evolution of the anisotropy is revealed by neutron powder diffraction data from 18 to 700 K, where the “breathing”-like kagome structure evolves into an ideal kagome lattice at higher temperature. Meanwhile, the deviation between the experimental and calculated results on heat capacity at high temperature and the softening of optical phonon modes in Raman spectra suggest the presence of anharmonic phonons in Fe3Sn2, which is responsible for the degeneracy of lattice thermal conductivity at high temperature. Our study indicates that Fe3Sn2 possesses a promising future in the design and development of topological, spintronic as well as thermoelectric devices.