CONICET | Buscador de Institutos y Recursos Humanos

In order to develop high-density information recording devices with storage densities above terabits/cm2, it is necessary to simultaneously achieve high thermal stability at operation temperatures and high recording rates. However, for area data density above terabits/cm2 the size of the bit approaches the superparamagnetic limit where the thermal fluctuations degrade the stability of the magnetization. Moreover, actual standard requirements for applications imply that a 95% of the bit magnetization must remain over a period of ten years and the possibility of subnanosecond magnetization switching times. Perpendicularly magnetized ultrathin films made of high coercivity materials are used with the intention of overcome the superparamagnetic limit, in combination with heat-assisted magnetization reversal (HAMR) to perform a suitable recording. The HAMR method is used in order to reduce temporarily the high coercitive field, during the writing process, by a localized heating above the critical temperature, such as the obtained with a laser pulse. Recently, a single model of the HAMR process over ultrathin films with strong anisotropy has been suggested [Phys Rev. B 84, 094431 (2011)], which is based in the ferromagnetic Ising Model and where the laser pulse is emulated by time-dependent Gaussian temperature profile. This model allowed to study the kinetics of nucleation and growth of the magnetic domains by means of Monte Carlo simulations, and to determine the dynamic spinodal corresponding to the crossover between multidroplet and single droplet nucleation regimes. In this work, we implemented a code with a variant of the described model where the external magnetic field and the time-dependent temperature profile are synchronized, and then simulated the magnetization reversal process. The interface dynamics and the thermal stability of the domains obtained by HAMR were investigated as a function of the strength of the magnetic field and the elapsed time of the temperature profile, for different system sizes.