Surface anisotropy in nanomagnets: transverse or Néel ?
arXiv:cond-mat/0307436 · doi:10.1016/j.jmmm.2003.12.1354
Abstract
Through the hysteresis loop and magnetization spatial distribution we study and compare two models for surface anisotropy in nanomagnets: a model with transverse anisotropy axes and Néel's model. While surface anisotropy in the transverse model induces several jumps in the hysteresis loop because of the cluster-wise switching of spins, in the Néel model the jumps correspond to successive {\it coherent partial rotations} of the whole bunch of spins. These calculations together with experimental results suggest that Néel's model for surface anisotropy is more appropriate.
12 pages, 6 eps figures