Magnetic asymmetry induced anomalous spin-orbit torque in IrMn

Journal Article · Mon May 04 00:00:00 EDT 2020 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.101.184403· OSTI ID:1617780

Zhou, Jing ^[1]; Shu, Xinyu ^[1]; Liu, Yaohua ^[2]; wang, Xiao ^[3]; Lin, Weinan ^[1]; Chen, Shaohai ^[1]; Liu, Liang ^[1]; Xie, Qidong ^[1]; Hong, Tao ^[2]; Yang, Ping ^[1]; Yan, Binghai ^[4]; Han, Xiufeng ^[3]; Chen, Jingsheng ^[1]

---

1. National Univ. of Singapore (Singapore)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. Chinese Academy of Sciences (CAS), Beijing (China)
4. Weizmann Inst. of Science, Rehovot (Israel)

We demonstrate an anomalous spin-orbit torque induced by the broken magnetic symmetry in the antiferromagnet IrMn. We study the magnetic structure of three phases of IrMn thin films using neutron diffraction technique. The magnetic mirror symmetry $\mathcal{M}{}^{\text{'}}$ is broken laterally in both $\mathrm{L}{1}_0\text{-}\mathrm{IrMn}$ and $\mathrm{L}{1}_2\text{-}\mathrm{IrM}{\mathrm{n}}_3$ but not $\gamma \text{-}\mathrm{IrM}{\mathrm{n}}_3$ . We observe an out-of-plane dampinglike spin-orbit torque in both $\mathrm{L}{1}_0\text{-}\mathrm{IrMn}$ /permalloy and $\mathrm{L}{1}_2\text{-}\mathrm{IrM}{\mathrm{n}}_3$ /permalloy bilayers but not in $\gamma \text{-}\mathrm{IrM}{\mathrm{n}}_3$ /permalloy. This is consistent with both the symmetry analysis on the effects of a broken $\mathcal{M}{}^{\text{'}}$ on spin-orbit torque and the theoretical predictions of the spin Hall effect and the Rashba-Edelstein effect. In addition, the measured spin-orbit torque efficiencies are 0.61 ± 0.01, 1.01 ± 0.03, and 0.80 ± 0.01 for the $\mathrm{L}{1}_0,\mathrm{L}{1}_2$ , and γ phases, respectively. Our work highlights the critical roles of the magnetic asymmetry in spin-orbit torque generation.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1617780
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 18 Vol. 101; ISSN 2469-9950; ISSN PRBMDO
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY