Domain walls in Fe(001) bicrystals—thickness dependence and field-induced transitions

Abstract Magnetic domain walls (DW's) formed at the grain boundary (GB) of epitaxial bicrystal Fe(0 0 1) films, thickness t = 50 and 70 nm, were studied by magnetic force microscopy. The “as-grown” samples displayed DW's with different magnetic contrast profiles yielding a single peak for t = 50 nm and a double peak with a change of sign at the centre of the wall for t = 70 nm . For t =50 nm the wall is characterised as an asymmetric Bloch wall. The double peak of the 70 nm thick film transformed into a single peak characteristic for a charged wall, when a field of 30 mT was applied along the GB. At remanence this domain wall relaxed to a regular Bloch wall divided into segments of alternating signs.