Disentanglement of Spin-Orbit Torques in Pt/Co Bilayers with the Presence of Spin Hall Effect and Rashba-Edelstein Effect

Ye Du, Hiromu Gamou, Saburo Takahashi, Shutaro Karube, Makoto Kohda, Junsaku Nitta

研究成果: Article査読

17 被引用数 (Scopus)

抄録

We demonstrate a quantitative disentanglement of current-induced spin-orbit torques (SOTs) in Pt/Co bilayers, where both the spin Hall effect (SHE) and the Rashba-Edelstein effect (REE) are present. The SOTs originating from the SHE in bulk Pt and from the REE at substrate (sub.)/Pt and Pt/Co interfaces are successfully disentangled and quantified utilizing harmonic Hall measurements, by taking advantage of different characteristic lengths between the two effects during spin-current transport. The fieldlike (FL) torque in our samples originates from the REE, while both SHE and REE contribute to the dampinglike (DL) torque. The experimentally extracted transport characteristic lengths in bulk Pt (an effective spin-diffusion length) are 1.8-3.0 nm, while those at Pt interfaces (an effective REE thickness) are 0.2-0.6 nm. The extracted REE-induced FL torque (and DL torque) efficiencies at sub./Pt and Pt/Co interfaces are of the same order of magnitude, but of opposite signs, which is consistent with the REE scenario. The origin of the observed temperature-dependent SOT sign reversal is clarified with our disentanglement analysis, demonstrating the significant role of the REE at both sub./Pt and Pt/Co interfaces, in contributing to the overall SOTs, as the thickness of the heavy-metal layer is thinner than its spin-diffusion length or comparable to a REE thickness.

本文言語English
論文番号054014
ジャーナルPhysical Review Applied
13
5
DOI
出版ステータスPublished - 2020 5

ASJC Scopus subject areas

  • 物理学および天文学(全般)

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