Magnetic properties of self-assembled interacting nanoparticles

The temperature-dependent magnetization and the hysteresis properties (remanence and coercivity) of magnetic nanoparticle arrays are studied by Monte Carlo simulations. An oscillatory variation of the remanence with layer coverage and accompanying peaks in the coercive field are predicted at low temperatures, due to dipolar interparticle interactions. The blocking temperature of the arrays decreases with the inverse cube of the interparticle spacing (T(b)similar tod(-3)) and it remains almost unchanged with film thickness above one monolayer. Our results are compared with recent experiments on self-assembled Co nanoparticle arrays. (C) 2002 American Institute of Physics.