Magnetization switching through giant spin-orbit torque in a magnetically doped topological insulator heterostructure
Magnetization switching through giant spin-orbit torque in a magnetically doped topological insulator heterostructure
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DOI：
10.1038/nmat3973
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发表时间：
2014-07-01
期刊：
影响因子：
41.2
通讯作者：
Wang, Kang L.
中科院分区：
文献类型：
--
作者：
Fan, Yabin;Upadhyaya, Pramey;Wang, Kang L.
近年来在重金属/铁磁异质结构（HMFHs）中出现的面内电流诱导的磁化开关引起了人们对大自旋-轨道耦合（SOC）引起的自旋力矩的关注。鉴于其固有的强荷电性，拓扑绝缘子有望成为探索自旋轨道转矩（SOT）相关物理的有希望的候选者。本文通过实验证明了在掺铬TI双层异质结构中，平面内电流诱导的巨大SOT的磁化开关。在1.9 K时，开关所需的临界电流密度低于8.9 x 10(4) A cm（-2）。此外，利用二次谐波方法测量有效自旋轨道场，对SOT进行了标定。有效场电流比和自旋-霍尔角切线几乎比报道的HMFHs大3个数量级。双层异质结构所表现出的巨大SOT和高效的电流感应磁化开关可能会导致创新的自旋电子学应用，如超低功耗存储和逻辑器件。
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 x 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.