论文标题
通过短应变脉冲激发磁弹性膜中高频磁通模式的激发
Excitation of high-frequency magnon modes in magnetoelastic films by short strain pulses
论文作者
论文摘要
开发用于生成自旋波的能源高效技术（镁元素）对于实施低衰减自旋波的逻辑电路和记忆元素很重要。实现这一目标的一种有希望的方法是基于将短应变脉冲注射到铁磁膜中，并在旋转和菌株之间具有强磁弹性耦合。在这里，我们报告了Fe $ _ {81} $ ga $ _ {19} $胶片中的磁化和应变动力学的微磁弹性模拟，由picsecond和nansecond osecond osecond osstrate在GAAS底物中产生的胶片，由经过光学或电气冲动的传感器在GAAS底物中产生。通过耦合Landau-Lifshitz-Gilbert和弹性动力学方程式进行的数值解和弹性动力学方程式进行的模拟表明，注入的应变脉冲会诱导铁磁性膜中的不均匀磁化进攻。该进动持续长达1 ns，可以视为具有站立旋转波的形式的木棒模式的叠加。对于Fe $ _ {81} $ ga $ _ {19} $具有纳米级厚度的胶片，在自由表面（固定）磁性边界条件下显示了多达七（六）个不同的模式。值得注意的是，具有适当形状和持续时间的声脉冲可以激发具有超过1 Thz的磁杆模式，但经受了中等外部磁场的影响。这一发现表明，短应变脉冲代表了用于实施高速镁性装置所需的THZ旋转波的有前途的工具。
Development of energy efficient techniques for generation of spin waves (magnons) is important for implementation of low-dissipation spin-wave-based logic circuits and memory elements. A promising approach to achieve this goal is based on the injection of short strain pulses into ferromagnetic films with a strong magnetoelastic coupling between spins and strains. Here we report micromagnetoelastic simulations of the magnetization and strain dynamics excited in Fe$_{81}$Ga$_{19}$ films by picosecond and nanosecond acoustic pulses created in a GaAs substrate by a transducer subjected to an optical or electrical impulse. The simulations performed via the numerical solution of the coupled Landau-Lifshitz-Gilbert and elastodynamic equations show that the injected strain pulse induces an inhomogeneous magnetization precession in the ferromagnetic film. The precession lasts up to 1 ns and can be treated as a superposition of magnon modes having the form of standing spin waves. For Fe$_{81}$Ga$_{19}$ films with nanoscale thickness, up to seven (six) distinct modes have been revealed under free-surface (pinning) magnetic boundary conditions. Remarkably, magnon modes with frequencies over 1 THz can be excited by acoustic pulses with an appropriate shape and duration in the films subjected to a moderate external magnetic field. This finding shows that short strain pulses represent a promising tool for the generation of THz spin waves necessary for the implementation of high-speed magnonic devices.
