Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
Nat Commun. 2019 Jan 16;10(1):233. doi: 10.1038/s41467-018-08181-y.
Different symmetry breaking ways determine various magnetization switching modes driven by spin-orbit torques (SOT). For instance, an applied or effective field parallel to applied current is indispensable to switch magnetization with perpendicular anisotropy by SOT. Besides of this mode, here we experimentally demonstrate a distinct field-free switching mode in a T-type magnetic system with structure of MgO/CoFeB/Ta/CoFeB/MgO where a perpendicular layer with tilted easy axis was coupled to an in-plane layer with a uniaxial easy axis. Current was applied orthogonal to both easy axes and thus also normal to an in-plane effective field experienced by the perpendicular layer. Dynamic calculation shows perpendicular layer could be switched at the same time as the in-plane layer is switched. These field-free switching modes realized in the same T-type magnetic system might expedite the birth of multi-state spin memories or spin logic devices which could be operated by all electric manners.
不同的对称破缺方式决定了由自旋轨道扭矩（SOT）驱动的各种磁化翻转模式。例如，对于具有垂直各向异性的磁体，通过 SOT 翻转其磁化方向需要施加与电流方向平行的外磁场或有效磁场。除了这种模式之外，我们还在 MgO/CoFeB/Ta/CoFeB/MgO 结构的 T 型磁体系统中实验演示了一种独特的无场切换模式，其中具有倾斜易轴的垂直层与具有单轴易轴的平面层耦合。电流垂直于两个易轴施加，因此也垂直于垂直层所经历的平面内有效磁场。动力学计算表明，当平面层被切换时，垂直层也可以同时被切换。这些在相同 T 型磁体系统中实现的无场切换模式可能会加速多态自旋存储器或自旋逻辑器件的诞生，这些器件可以通过全电方式操作。
