NONHOMOGENEOUS MAGNETIZATION REVERSAL IN 2D ISING CLUSTERS

We have performed Monte Carlo simulations on 2D circular Ising cluster s, studying the distribution of the magnetization within the cluster a s well as the magnetization reversal process when an applied external field is suddenly changed. We have shown that for highly anisotropic s ystems (the Ising-like limit), the magnetization reversal process is n ot uniform in a wide range of temperatures. Spins having a lower coord ination at cluster edges drive the reversal process, acting as nucleat ion centers. We have found that there is a connection between the roug hness transition temperature and the differences in the time evolution patterns of the magnetization. Our simulations agree with experimenta l results on magnetization reversal of single domain particles. (C) 19 96 American Institute of Physics.