Magnetization switching in nanoscale ferromagnetic grains: simulations   with heterogeneous nucleation
  We present results obtained with various types of heterogeneous nucleation in a kinetic Ising model of magnetization switching in single-domain ferromagnetic nanoparticles. We investigate the effect of the presence of the system boundary and make comparison with simulations on periodic lattices. We also study systems with bulk disorder and compare how two different types of disorder influence the switching behavior. 
M. Kolesik, H. L. Richards, M. A. Novotny, Per Arne Rikvold and   Per-Anker Lindgard