Microscopical test of current theories of magnetic wall motion

Magnetic wall motion and interaction with crystal defects were observed on in situ strained Ni- and 83Ni17Fe crystals by electron microscopy. Contrary to the assumptions of the “conservative force” and “Wandwölbung” model neither continuous wall motion prior to jumps nor piling up of dislocations by traversing walls with wall pinning were observed. Displacements of dislocations due to walls did occur, however, only at high strains. Pronounced wall pinning occurred at grain boundaries, slip traces, inclusions and holes. Demagnetizing fields, giving rise to reverse wall motion, and interaction between walls were negligible only at low fields.