Nucleation in Ising ferromagnet by a field spatially spreading in time

The nucleation in Ising ferromagnet has been studied by Monte Carlo simulation. Here, unlike the earlier studies, the magnetic field is spreading over the space in time. The nucleation time is observed to increase as compared to that in the case of static field. The clusters of negative spins are observed to grow from the centre. The growth of effective magnetisation is studied with temperature and the strength of spreading magnetic field. The ratio of nucleation time and effective time is also studied with strength of spreading magnetic field. The effective time would introduce itself as a new scale of time in the case of nucleation by spatially spreading magnetic field.