Influence of surface anisotropy on the magnetization reversal of nanoparticles

Abstract

The influence of surface anisotropy on the magnetization processes of\nmaghemite nanoparticles with ellipsoidal shape is studied by means of Monte\nCarlo simulations. Radial surface anisotropy is found to favor the formation of\nhedgehog-like spin structures that become more stable as the surface anisotropy\nconstant at the surface $k_S$ is increased form the value at the core. We have\nstudied the change in the low temperature hysteresis loops with the particle\naspect ratio and with $k_S$, finding a change in the magnetization reversal\nmode as $k_S$ or the particle elongation is increased.\n