Energy barrier enhanced by higher order magnetic anisotropy terms

We have studied the effects of higher order magnetic anisotropy terms on the irreversible switching field, the energy barrier, and the dynamics of magnetization switching of an uniaxial fine particle. The higher order terms effectively enhance the energy barrier without notable change in the switching field, enabling us to attain both saturation recording and good thermal stability. It is found that dynamics of the magnetization vector slightly slows down due to the presence of the higher order terms, but the effect is very small when they are not so large with respect to the lowest order anistropy term.