TY - JOUR
T1 - Effect of Rashba interaction at normal metal/insulator interface on spin-orbit torque of ferromagnet/normal metal/insulator trilayers
AU - Park, Eun Sang
AU - Min, Byoung Chul
AU - Koo, Hyun Cheol
AU - Kim, Kyoung Whan
AU - Lee, Kyoung Jin
PY - 2019/12/1
Y1 - 2019/12/1
N2 - Based on a spin drift-diffusion model, we theoretically investigate the spin-orbit torque in ferromagnet/normal metal/insulator trilayers with considering the Rashba interfacial spin-orbit coupling at the normal metal/insulator interface. We find that the spin-orbit torque shows the opposite normal-metal-thickness dependences for the bulk spin-orbit coupling effect in the normal metal layer and for the interfacial spin-orbit coupling effect at the normal metal/insulator interface, offering a way to disentangle these two spin-orbit coupling effects. Moreover, we show that the conventional interpretation based on the bulk spin-orbit coupling effect overestimates the spin Hall angle and underestimates the spin diffusion length of the normal metal layer, when the interfacial contribution is non-negligible. Our result, a concise analytic expression of the spin-orbit torque considering both bulk and interface spin-orbit coupling effects, will be useful to design and interpret experiments on spin-orbit torque experiments in ferromagnet/normal metal/insulator trilayers.
AB - Based on a spin drift-diffusion model, we theoretically investigate the spin-orbit torque in ferromagnet/normal metal/insulator trilayers with considering the Rashba interfacial spin-orbit coupling at the normal metal/insulator interface. We find that the spin-orbit torque shows the opposite normal-metal-thickness dependences for the bulk spin-orbit coupling effect in the normal metal layer and for the interfacial spin-orbit coupling effect at the normal metal/insulator interface, offering a way to disentangle these two spin-orbit coupling effects. Moreover, we show that the conventional interpretation based on the bulk spin-orbit coupling effect overestimates the spin Hall angle and underestimates the spin diffusion length of the normal metal layer, when the interfacial contribution is non-negligible. Our result, a concise analytic expression of the spin-orbit torque considering both bulk and interface spin-orbit coupling effects, will be useful to design and interpret experiments on spin-orbit torque experiments in ferromagnet/normal metal/insulator trilayers.
KW - Spin-orbit torque
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U2 - 10.1016/j.cap.2019.08.025
DO - 10.1016/j.cap.2019.08.025
M3 - Article
AN - SCOPUS:85071634510
VL - 19
SP - 1362
EP - 1366
JO - Current Applied Physics
JF - Current Applied Physics
SN - 1567-1739
IS - 12
ER -