Assessment of local variations in the coercivity of magneto-optical media

Locally varying deposition conditions and substrate characteristics of magneto-optic media may alter the domain nucleation, growth, and collapse mechanisms of the film. The use of a static tester and basic image processing equipment permits qualitative observations of anomalous domain nucleation, growth, and collapse phenomena. We present example images for a Co/Pt sample and several TbFeCo films that depict symmetrical domain expansion and collapse, directional preference for domain wall motion, domain collapse from submicroscopic domain remnants, and anomalous domain nucleation and expansion as a function of position on the sample.