Analysis of the magnetization dynamics near the Curie temperature in CoPt multilayer granular media: case study for heat-assisted magnetic recording

Heat-assisted magnetic recording (HAMR) has been shown to satisfy an increased data storage need of hard disk drives by enabling the writing of high-anisotropy materials such as FePt. Modelling the magnetization dynamics near the Curie temperature (T_c) is crucial when predicting the limits of HAMR or any technology that relies on fast, high temperature magnetization control. However, there are some differences in the behavior of magnetic grains under conditions important to HAMR, such as cooling rate and magnetic field angle. Such differences arise from how thermal fluctuations are modeled in the Landau-Lifshitz-Bloch equation. Therefore, it is important to benchmark these results against experiments to validate theoretical models. Here, we model the switching probability of granular CoPt media with VAMPIRE’s atomistic simulator as preparation for experiments. Unlike FePt, CoPt thin-films serve as a good benchmark due to their tunable composition, allowing us to more freely change parameters like saturation magnetization, anisotropy and T_c.