Free Field Electric Switching of Perpendicularly Magnetized Thin Film by Spin Current Gradient
Free Field Electric Switching of Perpendicularly Magnetized Thin Film by Spin Current Gradient
复制标题
利用自旋电流梯度实现垂直磁化薄膜的自由场电切换
DOI：
10.1021/acsami.9b09146
复制
发表时间：
2019-08-21
影响因子：
9.5
通讯作者：
Chen, Jingsheng
中科院分区：
文献类型：
--
作者：
Chen, Shaohai;Yu, Jihan;Chen, Jingsheng
为了实现低能耗的高速非易失性磁存储器，重金属/铁磁（HM/FM）结构中通过自旋轨道扭矩进行垂直磁化的电切换最近引起了人们的广泛关注。传统上，需要打破对称性的外部面内磁场来实现垂直磁化的电切换。然而，无外场的电切换是将磁功能集成到集成电路器件中的先决条件。在这里，我们提出了一种利用 Pt/W/FM 结构中的 W 楔来诱导自旋电流梯度的新方法，这可以沿着楔厚度梯度方向产生面内等效场。我们通过实验证明了当电流沿着楔形厚度梯度方向时，在没有外部磁场的情况下垂直Co/Ni多层的确定性磁化翻转。我们的研究结果揭示了通过一种新的物理参数——双层楔形结构引起的不对称自旋电流——磁化强度的自由场电切换。
To realize high-speed nonvolatile magnetic memory with low energy consumption, electric switching of perpendicular magnetization by spin-orbit torque in the heavy metal/ferromagnetic (HM/FM) structure has recently attracted intensive attention. Conventionally, an external in-plane magnetic field for breaking the symmetry is required for achieving electric switching of perpendicular magnetization. However, electric switching without external field is the prerequisite for the integration of magnetic functionality into the integrated circuit devices. Here, we propose a new method of utilizing a W wedge in the Pt/W/FM structure to induce a spin current gradient, which can result in an in-plane equivalent field along the wedge thickness gradient direction. We experimentally demonstrate the deterministic magnetization switching of perpendicular Co/Ni multilayers without external magnetic field when the electric current is along the wedge thickness gradient direction. Our findings shed light on free field electric switching of magnetization by a new physical parameter-an asymmetric spin current induced by a bilayer wedge structure.