论文标题
界面氧化在生成自旋轨道扭矩中的作用
Role of interfacial oxidation in generation of spin-orbit torques
论文作者
论文摘要
我们报告说，在界面附近的铁磁层的氧化中，重金属/铁磁 - 金属双层中电流诱导的自旋轨道（SOT）强烈改变。我们使用旋转 - 托尔克（Ferromagnetic resonance）的胶片测量了PT/CO和PT/Ni $ _ {81} $ fe $ _ {19} $（pt/py）胶片的pt/co和pt/ni $ _ {81} $ fe $ _ {81} $ _ {81} $ _ {81} $ _ {81} $ _ {81} $ _ {81} $ _ {81} $ _ {81} $ _ {81} $ _ {81} $ _ {81} $ _ {81}的SOTS SOTS的SOTS。在PT/CO膜中，我们发现，尽管COO $ _X $层的绝缘性质，但界面附近的CO层的氧化仍增强了DL和FL SOT。 SOT的增强通过在PT/COO $ _X $接口上插入薄的Ti层消失，这表明SOTS在PT/COO $ _X $/CO膜中的主要来源是PT/COO $ _X $界面上的自旋 - 轨耦合。与PT/COO $ _X $/CO胶片相反，PT/PYO $ _X $/PY胶片中的SOT由散装旋转轨道耦合主导。我们的结果表明，PT/PY膜的界面氧化抑制了DL-SOT并逆转了FL-SOT的符号。 SOT的更改可以归因于通过插入绝缘Pyo $ _x $ layer引起的自旋混合电导的真实和虚构部分的变化。这些结果表明，界面氧化提供了一种操纵SOT的强度和迹象的有效方法。
We report that current-induced spin-orbit torques (SOTs) in heavy-metal/ferromagnetic-metal bilayers are strongly altered by the oxidation of the ferromagnetic layer near the interface. We measured damping-like (DL) and field-like (FL) SOTs for Pt/Co and Pt/Ni$_{81}$Fe$_{19}$ (Pt/Py) films using spin-torque ferromagnetic resonance. In the Pt/Co film, we found that the oxidation of the Co layer near the interface enhances both DL and FL SOTs in spite of the insulating nature of the CoO$_x$ layer. The enhancement of the SOTs disappears by inserting a thin Ti layer at the Pt/CoO$_x$ interface, indicating that the dominant source of the SOTs in the Pt/CoO$_x$/Co film is the spin-orbit coupling at the Pt/CoO$_x$ interface. In contrast to the Pt/CoO$_x$/Co film, the SOTs in the Pt/PyO$_x$/Py film are dominated by the bulk spin-orbit coupling. Our result shows that the interfacial oxidation of the Pt/Py film suppresses the DL-SOT and reverses the sign of the FL-SOT. The change of the SOTs can be attributed to the change of the real and imaginary parts of the spin mixing conductance induced by the insertion of the insulating PyO$_x$ layer. These results show that the interfacial oxidation provides an effective way to manipulate the strength and sign of the SOTs.
