Abstract

The structure and magnetization dynamics are investigated in a vortex spin-transfer nanooscillator, which is a three-layer spin-valve magnetic nanocolumn with a large diameter of 400 nm, under flowing spin-polarized current through it. The dynamic variation in the structure of vortices and their trajectory of motion are studied, using micromagnetic modeling, as a function of the value of the spin-polarized current. It is demonstrated that different modes of motion of vortices may exist: decaying oscillations of vortices, stationary oscillations of vortices, and the mode of switching polarity of one of vortices. The time for which different dynamic modes are settled is determined. The dependence of the oscillation frequency on the value of spin-polarized current is determined for the case of stationary dynamics of coupled vortices. It is shown that, at large values of current, switching of vortex polarity is only possible in a thick layer with the dynamic switching mechanism accompanied by generation of a vortex–antivortex pair. The software package for micromagnetic simulation, SpinPM, is used for numerical calculations of the dynamics of magnetic vortices.

中文翻译：

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自旋极化电流对大直径三层导电纳米圆柱中磁涡流动力学和结构变化的影响

摘要

在涡旋自旋转移纳米振荡器中研究了其结构和磁化动力学，该涡旋自旋转移纳米振荡器是三层自旋阀磁性纳米柱，直径为400 nm，流过自旋极化电流。使用微磁模型，研究了旋涡结构及其运动轨迹的动态变化，该变化是自旋极化电流值的函数。结果表明，可能存在不同的旋涡运动模式：旋涡的衰减振荡，旋涡的平稳振荡以及旋涡之一的极性转换模式。确定建立不同动态模式的时间。对于耦合涡旋的稳态动力学，确定了振荡频率对自旋极化电流值的依赖性。结果表明，在大电流值下，只有在厚层中才能实现涡流极性的转换，而动态切换机制会伴随产生涡旋-反涡旋对。用于微磁仿真的软件包SpinPM用于磁旋动力学的数值计算。