Wide domain walls and Bloch lines in Permalloy and Co-Fe films using Kerr effect microscopy

The recent development of scanning electron microscopy with spin polarization analysis has led to the observation of wide domain walls in thin films of Permalloy. This investigation provides further evidence for the existence of domain walls greater than 1 μm. The domain structure of patterned Permalloy and Co-Fe films was observed with longitudinal Kerr effect microscopy and high-speed image processing (video). The Permalloy films investigated have a thickness range of 0.5–5 μm and square dimensions of 100 μm. Surface domain wall width measurements over the range of film thicknesses are presented. Observations show chirality changes in the domain wall (Bloch lines) as well as Bloch line propagation in the presence of fields.