Nucleation theory and the phase diagram of the magnetization-reversal transition

The phase diagram of the dynamic magnetization-reversal transition in pure Ising systems under a pulsed field competing with the existing order can be explained satisfactorily using the classical nucleation theory. Indications of single-droplet and multi-droplet nucleation and of the corresponding changes in the nucleation rates are clearly observed. The nature of the second time scale of relaxation, apart from the field-driven nucleation time, and the origin of its unusual large values at the phase boundary are explained from the disappearing tendency of kinks on the droplet wall surfaces after the withdrawal of the pulse. The possibility of scaling behaviour in the multi-droplet regime is identified and compared with the earlier observations.