Bloch lines and hysteresis in uniaxial magnetic crystals

Abstract

High-resolution Faraday microscopy using a laser light source reveals considerable complexities in the modes of oscillation of domain walls in single-crystal films of ferrimagnetic garnets, dependent on the prior magnetic field treatment. The observations are associated with the extent to which measured magnetization loops diverge from the theoretical form. The progressive nature of the deviation can be explained by recourse to magnetostatic theories, with the implication that the field treatments concerned generate Bloch lines in the walls.