Current-induced magnetization switching in all-oxide heterostructures

• Published in: Nature nanotechnology Vol. 14; no. 10; pp. 939 - 944
• Main Authors: Liu, Liang, Qin, Qing, Lin, Weinan, Li, Changjian, Xie, Qidong, He, Shikun, Shu, Xinyu, Zhou, Chenghang, Lim, Zhishiuh, Yu, Jihang, Lu, Wenlai, Li, Mengsha, Yan, Xiaobing, Pennycook, Stephen J., Chen, Jingsheng
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.10.2019; Nature Publishing Group
• Subjects: 142/126; 639/301/1005/1008; 639/301/119/1001; 639/766/119/2793; Anisotropy; Charge efficiency; Chemistry and Materials Science; Ferromagnetism; Heavy metals; Heterostructures; Information technology; Letter; Magnetic fields; Magnetic switching; Magnetism; Magnetization; Materials Science; Nanotechnology; Nanotechnology and Microengineering; Spin-orbit interactions; Spintronics; Strontium titanates; Substrates; Torque; Transition metals
• ISSN: 1748-3387; 1748-3395; 1748-3395
• DOI: 10.1038/s41565-019-0534-7

The electrical switching of magnetization through spin–orbit torque (SOT) 1 holds promise for application in information technologies, such as low-power, non-volatile magnetic memory. Materials with strong spin–orbit coupling, such as heavy metals 2 – 4 and topological insulators 5 , 6 , can convert a charge current into a spin current. The spin current can then execute a transfer torque on the magnetization of a neighbouring magnetic layer, usually a ferromagnetic metal like CoFeB, and reverse its magnetization. Here, we combine a ferromagnetic transition metal oxide 7 with an oxide with strong spin–orbit coupling 8 to demonstrate all-oxide SOT devices. We show current-induced magnetization switching in SrIrO 3 /SrRuO 3 bilayer structures. By controlling the magnetocrystalline anisotropy of SrRuO 3 on (001)- and (110)-oriented SrTiO 3 (STO) substrates, we designed two types of SOT switching schemes. For the bilayer on the STO(001) substrate, a magnetic-field-free switching was achieved, which remained undisturbed even when the external magnetic field reached 100 mT. The charge-to-spin conversion efficiency for the bilayer on the STO(110) substrate ranged from 0.58 to 0.86, depending on the directionality of the current flow with respect to the crystalline symmetry. All-oxide SOT structures may help to realize field-free switching through a magnetocrystalline anisotropy design. All-electrical switching of magnetization holds promise for applications in information technologies with low power consumption. Here, current-induced spin–orbit torque switches the magnetization in SrIrO 3 /SrRuO 3 bilayer structures at 70 K in the absence of an external magnetic field.