CHARACTERIZATION OF MICROSTRUCTURAL DEFECTS FROM TEMPERATURE-DEPENDENCE OF DOMAIN-WALL COERCIVE FIELD

The steep temperature dependence of the domain wall coercive field, H- CW(T), of highly anisotropic rare earth magnetic garnet films, recentl y described as a piece-wise exponential curve, was analysed. The quant itative analysis revealed the H-CW(T)shape to be caused by the exponen tial temperature dependence of the anisotropy field. modified by funct ions describing the efficiency of the wall-defects interaction, at lea st follow different sets of defects. Characteristic periods of the two sets of defects were found and the defects were identified in one cas e with point defects caused by local fluctuation of the anisotropy con stant at sites of individual rare earth ions in the crystal lattice an d in the other case with fluctuation of local stresses due to local fl uctuation of the material composition.