Microwave properties and anisotropy field distribution in nanogranular Fe-Co-Al-O films

We have investigated the microwave properties of a set of Co-Fe-Al-O films with different thicknesses. The films show a well-defined in-plane anisotropy due to the bias field applied during deposition. The resonance frequency is determined through the scattering parameters measured with a vector network analyzer and a probing station connected to a coplanar waveguide. The results show that the resonance peak features depend on the direction of the applied/RF field and on the applied field history. Index Terms--Anisotropy, FeCo films, ferromagnetic resonance, magnetic thin films, microwave properties, nanogranular films.