Longitudinal-transverse resonance and localization related to the random anisotropy in a -CoTbZr films

The properties of a resonance mode, the existence of which is related to the random local anisotropy of the sample, are reported. It was detected in amorphous CoZrTb thin films of low Tb content, in which there exists an in-plane uniaxial anisotropy field. Here the angular dependence of the mode is shown. In agreement with theory, it changes from a pure longitudinal to a mixed longitudinal transverse and a pure transverse state as a function of the orientation of the external field. The process is accompanied by the development of a very pronounced Anderson localization process due to the high value of the Tb related local anisotropy Kl.