A numerical investigation of stripe chopping in thin films with perpendicular anisotropy

The effect of bias field on stripe chopping margins in thin films with anisotropy perpendicular to the plane of the material has been investigated by numerical integration of the Landau-Lifshitz-Gilbert equation. The chopping margin increases with increasing bias field (corresponding to reduced initial wall-wall separation) when a uniform external field is applied. Horizontal Bloch line (HBL) formation is suppressed at large bias fields, and this suppression is responsible for the large margin that is seen. When an external field typical of a conductor loop above the sample is used, the margins are significantly reduced. In this case, the structure of the wall is significantly more complex and multiple HBLs are frequently seen in the wall