Magnetic switching driven by nanosecond scale heat and magnetic field pulses: An application of macrospin Landau-Lifshitz-Bloch model

High-temperature (near Curie-point) magnetization-behavior in materials with strong-perpendicular-magnetocrystalline-anisotropy has recently gained importance due to potential applications in thermally/heat-assisted-magnetic-recording (TAR/HAMR) systems. We have implemented a macrospin-model within the Landau-Lifshitz-Bloch formalism for strongly exchange-coupled CoNi/Pd multilayers subject to nanosecond-scale localized-heat and magnetic-field pulses. The temperature dependence of the longitudinal-susceptibility, as determined from a single-fitting-parameter of the experimental coercive-field, is consistent with the previously reported ab initio calculations. We demonstrate that this model is able to predict the full map of switching-speed as a function of magnetic-field and local-temperature providing a robust tool for the evaluation of this and similar material systems in TAR/HAMR applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4772486]