Magnetic field dependence of the domain wall mass

Abstract

The dependence of the 180 °-Block domain wall mass in a ferromagnetic thin film on a magnetic field parallel to the plane of the film was studied theoretically. The Slonczewski theory of the domain wall dynamics was generalized to take into account the distortion of the domain wall structure by the in-plane magnetic field. An essential aspect of the analysis is that both polar angles determining local directions of magnetic moments within the wall depend upon the distance from the symmetry plane of the wall. The case of an in-place field parallel to the domain wall was studied in detail. For small in-plane field H the domain wall mass is approximately m/mo = 1−(π/2)(Q+1)h+0 (h2 1n h), where Q = K/2πM2 and h = MH/2K (M is the saturation magnetization, K is the uniaxial anisotropy constant and mo is the Döring mass). Calculations of the domain wall mass for a field making a small angle with the domain wall were also done as well as an estimate of the influence of the cubic anisotropy on the domain wall mass.