Micromagnetic Studies of Laser-Induced Magnetization Dynamics in FePt–C Films

Laser-induced magnetization dynamics has been studied extensively and involves the thermally induced magnetization switching and the assistance to break the symmetry of switching. In this paper, the effects of the laser focus on the laser heating and the temperature profile in the FePt-C granular media are determined by measuring the Kerr signal via all-optical time-resolved magneto-optical Kerr effect. Based on that, we utilize the hybrid Monte Carlo micromagnetic method to simulate laser-induced magnetization dynamics in FePt-C films with different external magnetic fields and laser fluences. The results show that the magnetization dynamics includes an ultrafast demagnetization, a slower magnetization recovery, and a long-timescale magnetization reversal or the continuing recovery, depending on the magnitude of laser fluence and the external magnetic field.