| Popis: |
Dynamics of magnetization M driven by microwave are derived analytically from the nonlinear Landau–Lifshitz–Gilbert equation. Analytical M and susceptibility are obtained self-consistently under a positive circularly polarized microwave field, $\mathbf{h} = \left(h \cos \omega t,h \sin \omega t,0 \right)$ , with frequency $\omega$ , which is perpendicular to a static field, $\mathbf{H} = \left(0,0,H \right)$ . It is found that the orbital of M is always a cone along H . However, with increasing h the polar angle $\theta$ of M initially increases, then keeps 90° when $\mathit{h} \unicode{x2A7E} \mathit{h}_{0} = \alpha \omega /\gamma $ in ferromagnetic resonance (FMR) mode, where $\alpha$ is Gilbert damping constant and $\gamma$ is gyromagnetic ratio. These effects result in a nonlinear variation of FMR signal as h increases to $h \unicode{x2A7E} h_{0}$ , where the maximum of resonance peak decreases from a steady value, linewidth increases from a decreasing trend. These analytical solutions provide a complete picture of the dynamics of M with different h and H . |
