1] Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA [2].
Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA.
Nat Mater. 2014 Jul;13(7):699-704. doi: 10.1038/nmat3973. Epub 2014 Apr 28.
Recent demonstrations of magnetization switching induced by in-plane current in heavy metal/ferromagnetic heterostructures (HMFHs) have drawn great attention to spin torques arising from large spin-orbit coupling (SOC). Given the intrinsic strong SOC, topological insulators (TIs) are expected to be promising candidates for exploring spin-orbit torque (SOT)-related physics. Here we demonstrate experimentally the magnetization switching through giant SOT induced by an in-plane current in a chromium-doped TI bilayer heterostructure. The critical current density required for switching is below 8.9 × 10(4) A cm(-2) at 1.9 K. Moreover, the SOT is calibrated by measuring the effective spin-orbit field using second-harmonic methods. The effective field to current ratio and the spin-Hall angle tangent are almost three orders of magnitude larger than those reported for HMFHs. The giant SOT and efficient current-induced magnetization switching exhibited by the bilayer heterostructure may lead to innovative spintronics applications such as ultralow power dissipation memory and logic devices.
最近在重金属/铁磁异质结构（HMFHs）中展示的平面电流诱导磁化翻转引起了人们对大自旋轨道耦合（SOC）产生的自旋扭矩的极大关注。鉴于固有强 SOC，拓扑绝缘体（TIs）有望成为探索自旋轨道扭矩（SOT）相关物理的有前途的候选者。在这里，我们通过在掺杂铬的 TI 双层异质结构中平面电流诱导的巨大 SOT 实验证明了磁化切换。在 1.9 K 下，切换所需的临界电流密度低于 8.9×10(4) A cm(-2)。此外，通过使用二次谐波方法测量有效自旋轨道场来校准 SOT。有效场与电流比和自旋霍尔角正切值几乎比 HMFHs 报道的大三个数量级。双层异质结构表现出的巨大 SOT 和高效电流诱导的磁化翻转可能会导致创新的自旋电子学应用，例如超低功耗存储和逻辑器件。
