Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
Department of Physics and Astronomy, University of California, Riverside, California 92521, USA.
Phys Rev Lett. 2023 Feb 24;130(8):086703. doi: 10.1103/PhysRevLett.130.086703.
Unidirectional spin Hall magnetoresistance (USMR) has been widely reported in the heavy metal/ferromagnet bilayer systems. We observe the USMR in Pt/α-Fe_{2}O_{3} bilayers where the α-Fe_{2}O_{3} is an antiferromagnetic (AFM) insulator. Systematic field and temperature dependent measurements confirm the magnonic origin of the USMR. The appearance of AFM-USMR is driven by the imbalance of creation and annihilation of AFM magnons by spin orbit torque due to the thermal random field. However, unlike its ferromagnetic counterpart, theoretical modeling reveals that the USMR in Pt/α-Fe_{2}O_{3} is determined by the antiferromagtic magnon number with a non-monotonic field dependence. Our findings extend the generality of the USMR which pave the ways for the highly sensitive detection of AFM spin state.
单向自旋霍尔磁电阻（USMR）在重金属/铁磁体双层系统中得到了广泛的报道。我们在 Pt/α-Fe_{2}O_{3} 双层系统中观察到了 USMR，其中 α-Fe_{2}O_{3} 是一种反铁磁（AFM）绝缘体。系统的磁场和温度相关测量证实了 USMR 的磁振子起源。由于热随机场，自旋轨道扭矩导致 AFM 磁子的产生和湮灭失衡，从而产生 AFM-USMR。然而，与铁磁体不同，理论模型表明，Pt/α-Fe_{2}O_{3} 中的 USMR 由反铁磁磁子数量决定，且其与磁场呈非单调依赖关系。我们的发现扩展了 USMR 的普遍性，为 AFM 自旋态的高灵敏度检测铺平了道路。
