薄圆形铁磁纳米盘中的热涡旋动力学
Thermal vortex dynamics in thin circular ferromagnetic nanodisks
摘要：
研究了软铁磁材料薄圆盘中旋向涡旋运动的动力学问题。退磁场的计算使用二维格林函数的薄膜问题和快速傅立叶变换。在零温度下，Landau-Lifshitz-Gilbert方程的动力学模拟使用四阶Runge-Kutta积分。在拉格朗日乘子约束下，得到了理想位置处的纯涡初始条件。这些方法给出了涡回复力常数$k_F$和旋向频率的精确估计，表明涡核运动由Thiele方程描述，具有很高的精度。在有限温度下，将二阶Heun算法应用于具有热噪声和阻尼的Langevin动力学方程。在没有外部磁场的情况下，自发的回旋运动仅由热波动驱动。涡的径向位置和旋转速度的统计描述与玻尔兹曼分布确定的$k_F$和由涡旋回转质量$m_G=G^2/k_F$，分别，其中$G$是涡旋回转矢量。
英文摘要：
The dynamics of gyrotropic vortex motion in a thin circular nanodisk of soft ferromagnetic material is considered. The demagnetization field is calculated using two-dimensional Green's functions for the thin film problem and fast Fourier transforms. At zero temperature, the dynamics of the Landau-Lifshitz-Gilbert equation is simulated using fourth order Runge-Kutta integration. Pure vortex initial conditions at a desired position are obtained with a Lagrange multipliers constraint. These methods give accurate estimates of the vortex restoring force constant $k_F$ and gyrotropic frequency, showing that the vortex core motion is described by the Thiele equation to very high precision. At finite temperature, the second order Heun algorithm is applied to the Langevin dynamical equation with thermal noise and damping. A spontaneous gyrotropic motion takes place without the application of an external magnetic field, driven only by thermal fluctuations. The statistics of the vortex radial position and rotational velocity are described with Boltzmann distributions determined by $k_F$ and by a vortex gyrotropic mass $m_G=G^2/k_F$, respectively, where $G$ is the vortex gyrovector.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
