The temperature dependence of magnetic domain structure in cobalt monocrystals studied by SEM

The domain behaviour on the basal planes of cobalt monocrystals was investigated during a heating cycle. The study was carried out for specimen thicknesses in the range 0.8-1.9 mm using the type-I magnetic contrast in a scanning electron microscope (SEM). Because of the problems in imaging magnetic domains at the higher temperatures used and the complex character of the domain structure, digital image processing was applied to the original SEM images for their restoration, enhancement and analysis. The changes in both domain structure and type-I magnetic contrast are caused by the reduction in magnetocrystalline anisotropy energy with increasing temperature. The temperature of the phase transition between an open flux and a closed-flux domain configuration was found to be slightly dependent on the specimen thickness.