IRON WHISKER DOMAIN PATTERNS IMAGED BY GARNET-FILMS

Bismuth doped yttrium iron garnet thin films formed on the surfaces of a gadolinium gallium garnet substrate are used as magneto-optical ind icators for quantitative studies of the micromagnetics of an iron whis ker. The method does not require image processing. A field applied per pendicular to the whisker axis splits a 180 degrees domain wall into t wo 90 degrees sections slightly separated by a section magnetized in t he direction of the perpendicular field. A field along the axis of the whisker has a similar effect. Where the region between the two split 90 degrees sections intersect the surface, there is a magnetic charge that strongly affects the domain pattern of the indicator film. More g enerally, domain walls become visible because the local internal susce ptibility is greater at the walls than in the domains. The magneto-opt ical indicator can be used to measure both susceptibilities. (C) 1996 American Institute of Physics.