Non-destructive evaluation of YIG films by ferromagnetic resonance

A novel technique for evaluating thick YIG films by measuring the ferromagnetic resonance (FMR) linewidth on a localized area of the wafer is presented. The technique is based on the excitation of magnetostatic wave (MSW) resonance in a small area of the film under a bias magnetic field well. The well is created by a small hole in a soft-iron plate in close proximity to the film surface. The MSWs are excited by the electromagnetic fields emanating from a hole on the side of a waveguide. The technique has been used on films with thicknesses of around 100 mu m, yielding FMR linewidths comparable to those obtained with small resonators etched or cut from the film. These full-wafer measurements are not only nondestructive and simple to perform, but also allow probing of different areas of the film.<
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