An investigation of Ferromagnetic domains in surfaces inclined to the (110) plane of crystals of Silicon-iron

Abstract

The magnetic domain arrangements, in surfaces slightly inclined to (110) planes of Si-Fe crystals, have been studied by the Bitter pattern technique. The relationship between the pattern and the inclination of the surface to the (110) plane was examined by observing the patterns on crystals cut from thin sheets and then measuring the surface orientation by means of a two-circle goniometer. The results were checked by observing the changes in patterns as the surface of a thick and a thin crystal were ground through successive small angles to increase the inclination of the surface. It is concluded that as the inclination between the surface and the (110) plane is increased up to angles of about 10 -12 the resulting magnetostatic energy is minimised by the formation of reverse lozenges. The lozenges increase in number as the angle increases and eventually form a lace pattern which completely obscures the underlying domain arrangement. A pattern of reverse lozenges arranged in rows perpendicular to the [001] direction, a criss-cross pattern and a zig-zag pattern were frequently observed but could usually be removed by annealing. It is suggested that these patterns indicate the presence of strain. An arrangement of taxipole-like deposits has been investigated. The results suggest that this is a surface arrangement in which the approximately vectors point along the [100] and [010] directions at approximately 45 to the surface. The structure is considered to be a 'transverse' domain which is formed during demagnetisation and plays an important part in the nucleation process.