Time-resolved magnetization precession and reversal dynamics investigated using tunneling current and Kerr effect

Abstract

Magnetization precession and reversal dynamics in permalloy (Py) layer was studied using ns-time-scale spin-polarized tunneling current probing and ps-time-scale Kerr microscopy. In the time-resolved magneto-optical Kerr effect measurement, the precessional frequency increased with increasing external static field. The signal was fitted well with the calculation using Landau–Lifshitz–Gilbert equation of motion with the damping parameter α of 0.008, which corresponded to the value obtained for the film measured using a ferromagnetic resonance.