DOMAIN STUDIES IN SINGLE-CRYSTAL FERRITE MIG HEADS WITH IMAGE-ENHANCED, WIDE-FIELD, KERR MICROSCOPY

The magnetic domain structure at the media-facing surfaces of single-crystal ferrite metal-in-gap heads is investigated using the magnetooptical Kerr effect. Domain behavior depends strongly on the stress state and surface treatment of the head. The pole tips display coercive zig-zag domain walls, which are nucleated at the gap by write current pulses. For the samples studied, nucleation and motion of these walls is different between heads which exhibit small secondary pulses in the read-back signal and heads which do not.