TY - JOUR
T1 - Negative spin Hall magnetoresistance of normal metal/ferromagnet bilayers
AU - Kang, Min Gu
AU - Go, Gyungchoon
AU - Kim, Kyoung Whan
AU - Choi, Jong Guk
AU - Park, Byong Guk
AU - Lee, Kyung Jin
N1 - Funding Information:
We acknowledge discussion with V.P. Amin, P.H. Haney, and M.D. Stiles. K.-J.L. and B.G.P. acknowledge support from Samsung Research Funding Center of Samsung Electronics under Project Number SRFCMA1702-02. K.-W.K acknowledges support from the KIST Institutional Program (Project Nos. 2V05750 and 2E30600). G.G. acknowledges a support by the NRF under Grant (NRF-2019R1I1A1A01063594).
PY - 2020/12/1
Y1 - 2020/12/1
N2 - Interconversion between charge and spin through spin-orbit coupling lies at the heart of condensed-matter physics. In normal metal/ferromagnet bilayers, a concerted action of the interconversions, the spin Hall effect and its inverse effect of normal metals, results in spin Hall magnetoresistance, whose sign is always positive regardless of the sign of spin Hall conductivity of normal metals. Here we report that the spin Hall magnetoresistance of Ta/NiFe bilayers is negative, necessitating an additional interconversion process. Our theory shows that the interconversion owing to interfacial spin-orbit coupling at normal metal/ferromagnet interfaces can give rise to negative spin Hall magnetoresistance. Given that recent studies found the conversion from charge currents to spin currents at normal metal/ferromagnet interfaces, our work provides a missing proof of its reciprocal spin-current-to-charge-current conversion at same interface. Our result suggests that interfacial spin-orbit coupling effect can dominate over bulk effects, thereby demanding interface engineering for advanced spintronics devices.
AB - Interconversion between charge and spin through spin-orbit coupling lies at the heart of condensed-matter physics. In normal metal/ferromagnet bilayers, a concerted action of the interconversions, the spin Hall effect and its inverse effect of normal metals, results in spin Hall magnetoresistance, whose sign is always positive regardless of the sign of spin Hall conductivity of normal metals. Here we report that the spin Hall magnetoresistance of Ta/NiFe bilayers is negative, necessitating an additional interconversion process. Our theory shows that the interconversion owing to interfacial spin-orbit coupling at normal metal/ferromagnet interfaces can give rise to negative spin Hall magnetoresistance. Given that recent studies found the conversion from charge currents to spin currents at normal metal/ferromagnet interfaces, our work provides a missing proof of its reciprocal spin-current-to-charge-current conversion at same interface. Our result suggests that interfacial spin-orbit coupling effect can dominate over bulk effects, thereby demanding interface engineering for advanced spintronics devices.
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U2 - 10.1038/s41467-020-17463-3
DO - 10.1038/s41467-020-17463-3
M3 - Article
C2 - 32681024
AN - SCOPUS:85088089100
VL - 11
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
IS - 1
M1 - 3619
ER -