Magnetization curling in films used for perpendicular magnetic recording

Abstract

The magnetization-curling mode in a columnar-structure film with perpendicular magnetization is studied on the assumption that the film is a two-dimensional array of cylinders. The angular dependence of the nucleation field HN is calculated by the Ritz method and compared with that for the coherent-rotation mode. It is found that the magnetization rotates in the curling mode for a large reduced radius S and in the coherent-rotation mode for a small S. The angular dependence of HN is different from that in an infinite cylinder. If S is large, the magnetization rotates in the curling mode for any value of θ0, where θ0 is the angle between the applied field and the cylinder axis. When S is medium, the magnetization rotates in the coherent-rotation mode for a small θ0 and in the curling mode for a large θ0.