Coherent magnetization reversal of nanoparticles with crystal and shape anisotropy

We discuss coherent magnetization reversal in single-domain particles with cubic or uniaxial crystal anisotropy and present the derivation and simulat ion of the nucleation field in the important case of particles with shape a nisotropy and a random orientation of a cubic crystal anisotropy axis. We a nalyze the interplay of shape and crystal anisotropy as a function of cryst al orientation with respect to the applied field. In addition, we present s imulations for particles with uniaxial crystal anisotropy and derive the va lues for remanence and coercive field of an ensemble of particles from calc ulated hysteresis loops in each case. (C) 2001 American Institute of Physic s.