Dynamic distortion in a magnetic domain wall containing loosely spaced 2π VBLs

The dynamics of a magnetic domain wall containing vertical Bloch line winding pairs (2π VBL) are numerically investigated. The wall is of the kind found in thin film materials with a large anisotropy perpendicular to the plane of the film. The 2π VBLs are all of the same chirality and are periodically repeated along the wall at equal spacing. The wall is driven by an applied field perpendicular to the film plane, and the VBLs move gyrotropically. Starting from an equilibrium shape, the 2π VBLs distort. If the field is low enough, a new dynamic shape is established that is quite stable. Above a threshold, the distortion pulls the 2π VBLs apart into a π VBL chain before the dynamic equilibrium structure is established. This breakup is accompanied by a discontinuous jump in both wall and VBL mobility