Thermally assisted switching in FePt single-domain particles with a Gaussian distribution of temperature

Abstract

Magnetic nanoscale systems, including nanodots, nanofibers, nanowires and nanoparticles, are currently attracting great interest due to their interesting physical and promising applications in various fields, such as magnetic recording, sensors, target drugs and catalysts, as well as others. To achieve ultrahigh recording density, the method of heat assisted magnetic recording (HAMR) has been introduced. In this work, with the help of a Monte Carlo method, the mechanisms of thermally assisted magnetization switching in FePt single-domain particles driven by an external magnetic field are investigated, where the temperature in the particles is assumed to follow a Gaussian distribution. Two nucleation modes are observed for different distributions of temperature. One is initiated by many droplets, which join each other at the boundary of the system; the other is initiated by many droplets at the boundary, but in growth tending toward the inner part of the system. An inverse proportional relationship between the metastable lifetime and the distribution is also found.