Magnetization switching using topological surface states
Magnetization switching using topological surface states
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DOI：
10.1126/sciadv.aaw3415
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发表时间：
2019-08-01
期刊：
影响因子：
13.6
通讯作者：
Wu, Mingzhong
中科院分区：
文献类型：
--
作者：
Li, Peng;Kally, James;Wu, Mingzhong
拓扑绝缘体中的拓扑表面态(TSS)有望产生能够切换相邻铁磁体的自旋轨道扭矩。如果铁磁体是导电的，则可能没有这种效应，因为它可以完全抑制TSS，但如果铁磁体是绝缘的，它应该存在。本研究报告了由拓扑绝缘体Bi2Se3和绝缘铁磁体BaFe12O19组成的双层薄膜中的TSS诱导开关。Bi2Se3中的充电电流可以使BaFe12O19中的磁化强度上下切换。当磁化强度被一个场切换时，Bi2Se3中的电流可以使切换场减小约4000 Oe。3K下的开关效率是室温下的300倍，相当于铂/BaFe12O19的30倍。这些强烈的效应源于低温下由于表面电导率的增强和体电导率的降低而存在更明显的TS_s。
Topological surface states (TSSs) in a topological insulator are expected to be able to produce a spin-orbit torque that can switch a neighboring ferromagnet. This effect may be absent if the ferromagnet is conductive because it can completely suppress the TSSs, but it should be present if the ferromagnet is insulating. This study reports TSS-induced switching in a bilayer consisting of a topological insulator Bi2Se3 and an insulating ferromagnet BaFe12O19. A charge current in Bi2Se3 can switch the magnetization in BaFe12O19 up and down. When the magnetization is switched by a field, a current in Bi2Se3 can reduce the switching field by similar to 4000 Oe. The switching efficiency at 3 K is 300 times higher than at room temperature; it is similar to 30 times higher than in Pt/BaFe12O19. These strong effects originate from the presence of more pronounced TSSs at low temperatures due to enhanced surface conductivity and reduced bulk conductivity.