Lorentz Electron Microscope Observation of Domain Walls in Fe–Nd–B Alloy Permanent Magnets

Abstract
Domain and wall structures of sintered Fe77Nd15B8 permanent magnets have been examined by high voltage electron microscopy. A wall width of a 180° wall in a grain having the c-axis in the surface is about 50 Å, which agrees with that expected from a pure Bloch wall. However, a significant variation of a 180° wall image width along the c-axis was found, which is presumably due to a tilting of a wall plane with respect to the sample surface.