Effect of Rashba interaction at normal metal/insulator interface on spin-orbit torque of ferromagnet/normal metal/insulator trilayers

Eun Sang Park; Byoung Chul Min; Hyun Cheol Koo; Kyoung Whan Kim; Kyung Jin Lee

doi:10.1016/j.cap.2019.08.025

Effect of Rashba interaction at normal metal/insulator interface on spin-orbit torque of ferromagnet/normal metal/insulator trilayers

Eun Sang Park, Byoung Chul Min, Hyun Cheol Koo, Kyoung Whan Kim, Kyung Jin Lee

Research output: Contribution to journal › Article › peer-review

4 Citations (Scopus)

Abstract

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.

Original language	English
Pages (from-to)	1362-1366
Number of pages	5
Journal	Current Applied Physics
Volume	19
Issue number	12
DOIs	https://doi.org/10.1016/j.cap.2019.08.025
Publication status	Published - 2019 Dec

Bibliographical note

Funding Information:
This work was supported by the KIST Institutional program (Project Nos. 2V05750 , 2E29410 ). B.-C.M. and K.-W.K. acknowledge support from the National Research Council of Science & Technology (NST) (Grant No. CAP-16-01-KIST ). K.-W.K. acknowledges the German Research Foundation (No. SI 1720/2-1 ).

Funding Information:
This work was supported by the KIST Institutional program (Project Nos. 2V05750, 2E29410). B.-C.M. and K.-W.K. acknowledge support from the National Research Council of Science & Technology (NST) (Grant No. CAP-16-01-KIST). K.-W.K. acknowledges the German Research Foundation (No. SI 1720/2-1).

Publisher Copyright:
© 2019 Korean Physical Society

Keywords

Spin-orbit torque

ASJC Scopus subject areas

General Materials Science
General Physics and Astronomy

Access to Document

10.1016/j.cap.2019.08.025

Cite this

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title = "Effect of Rashba interaction at normal metal/insulator interface on spin-orbit torque of ferromagnet/normal metal/insulator trilayers",

abstract = "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.",

keywords = "Spin-orbit torque",

author = "Park, {Eun Sang} and Min, {Byoung Chul} and Koo, {Hyun Cheol} and Kim, {Kyoung Whan} and Lee, {Kyung Jin}",

note = "Funding Information: This work was supported by the KIST Institutional program (Project Nos. 2V05750 , 2E29410 ). B.-C.M. and K.-W.K. acknowledge support from the National Research Council of Science & Technology (NST) (Grant No. CAP-16-01-KIST ). K.-W.K. acknowledges the German Research Foundation (No. SI 1720/2-1 ). Funding Information: This work was supported by the KIST Institutional program (Project Nos. 2V05750, 2E29410). B.-C.M. and K.-W.K. acknowledge support from the National Research Council of Science & Technology (NST) (Grant No. CAP-16-01-KIST). K.-W.K. acknowledges the German Research Foundation (No. SI 1720/2-1). Publisher Copyright: {\textcopyright} 2019 Korean Physical Society",

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AU - Park, Eun Sang

AU - Min, Byoung Chul

AU - Koo, Hyun Cheol

AU - Kim, Kyoung Whan

AU - Lee, Kyung Jin

N1 - Funding Information: This work was supported by the KIST Institutional program (Project Nos. 2V05750 , 2E29410 ). B.-C.M. and K.-W.K. acknowledge support from the National Research Council of Science & Technology (NST) (Grant No. CAP-16-01-KIST ). K.-W.K. acknowledges the German Research Foundation (No. SI 1720/2-1 ). Funding Information: This work was supported by the KIST Institutional program (Project Nos. 2V05750, 2E29410). B.-C.M. and K.-W.K. acknowledge support from the National Research Council of Science & Technology (NST) (Grant No. CAP-16-01-KIST). K.-W.K. acknowledges the German Research Foundation (No. SI 1720/2-1). Publisher Copyright: © 2019 Korean Physical Society

PY - 2019/12

Y1 - 2019/12

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.

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Effect of Rashba interaction at normal metal/insulator interface on spin-orbit torque of ferromagnet/normal metal/insulator trilayers

Abstract

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