Effect of angle-dependent Gilbert damping due to spin pumping on the magnetization dynamics induced by spin current

Here we investigated magnetization dynamics induced by spin currents with including the angle-dependent Gilbert damping in macrospin model.In this work, we assumed no angular dependence of a,to understand the sole effect of the angle-dependent Gilbert damping.The effect of the angle-dependent Gilbert damping is significant for the microwave generation induced by the spin torque.We found the precession motion induced by the spin torque is significantly changed with varying the angle-dependent Gilbert damping. For the application of a microwave device, a monotonic variation of the precession frequency as a function of either current or magnetic field is desired. To design the monotonic variation, the angle-dependent Gilbert damping should be considered since it significantly affects the transition from the in-plane precession mode to out-of-plane one.