Enhanced spin-orbit torque via interface engineering in Pt/CoFeB/MgO heterostructures

Spin-orbit torque facilitates efficient magnetization switching via an in-plane current in perpendicularly magnetized heavy metal/ferromagnet heterostructures. The efficiency of spin-orbit-torque-induced switching is determined by the charge-to-spin conversion arising from either bulk or interfacial...

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Main Authors Lee, Hae-Yeon, Kim, Sanghoon, Park, June-Young, Oh, Young-Wan, Park, Seung-Young, Ham, Wooseung, Kotani, Yoshinori, Nakamura, Tetsuya, Suzuki, Motohiro, Ono, Teruo, Lee, Kyung-Jin, Park, Byong-Guk
Format Journal Article
LanguageEnglish
Published 19.03.2018
Subjects
Physics - Materials Science
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Summary:Spin-orbit torque facilitates efficient magnetization switching via an in-plane current in perpendicularly magnetized heavy metal/ferromagnet heterostructures. The efficiency of spin-orbit-torque-induced switching is determined by the charge-to-spin conversion arising from either bulk or interfacial spin-orbit interactions, or both. Here, we demonstrate that the spin-orbit torque and the resultant switching efficiency in Pt/CoFeB systems are significantly enhanced by an interfacial modification involving Ti insertion between the Pt and CoFeB layers. Spin pumping and X-ray magnetic circular dichroism experiments reveal that this enhancement is due to an additional interface-generated spin current of the nonmagnetic interface and/or improved spin transparency achieved by suppressing the proximity-induced moment in the Pt layer. Our results demonstrate that interface engineering affords an effective approach to improve spin-orbit torque and thereby magnetization switching efficiency.
DOI:10.48550/arxiv.1803.06961