Influence of in-plane anisotropy and eddy currents on the frequency spectra of the complex permeability of amorphous CoZr thin films

A broadband method for measuring the complex permeability of magnetic thin films, based on the measurement of the S parameters of a stripline and on the numerical solution of Laplace's equation according to the quasi-TEM (transverse electromagnetic) propagation mode, is presented. The method is applied to determine the permeability spectra of CoZr amorphous thin films in the 3 MHz to 3 GHz frequency range. The influence of the exciting magnetic field orientation with respect to the direction of the easy axis is studied. The influence of eddy current on the cutoff frequency observed for permeability spectra is analyzed.<
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