Giant efficiency for charge-to-spin conversion via the electron gas at the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">LaTiO</mml:mi><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo><mml:mi>δ</mml:mi></mml:mrow></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mi mathvariant="normal">SrTiO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math> interface
Jing Zhang, Jine Zhang, Xiang Chi, Runrun Hao, Weibin Chen, Huaiwen Yang, Dapeng Zhu, Qinghua Zhang, Weisheng Zhao, Hui Zhang, Jirong Sun
Abstract
Spin-to-charge interconversion has been extensively investigated to improve its efficiency of charge-to-spin conversion, realizing magnetic switching by the technique of low-power spin-orbit torque (SOT). The quasi-two-dimensional electron gas (q2DEG) formed at the interface between insulating ${\mathrm{SrTiO}}_{3}$ (STO) and ${\mathrm{LaTiO}}_{3+\ensuremath{\delta}}$ (LTO) is supposed to possess strong Rashba spin-orbit coupling. Here, we show that a charge current flowing along the LTO/STO interface, which hosts a q2DEG, can efficiently generate a spin current, producing a strong SOT on adjacent NiFe layer as confirmed by spin-torque ferromagnetic resonance. The maximal charge-to-spin conversion efficiency is as large as $\ensuremath{\sim}2.4$ at room temperature, appearing in the NiFe/LTO/STO structure with a LTO thickness of 4 nm. This efficiency is much larger than that of heavy meals. With the decrease of temperature, the conversion efficiency only exhibits a slight decrease, remaining $\ensuremath{\sim}1.5$ at 20 K. The present work reveals the great potential of conducting oxide interface for oxide-based spintronics.