Ferromagnetic Resonance in Thin Films of Permalloy

Microwave resonance measurements have been made in evaporated (82% Ni, 18% Fe) films of thickness 760 A to 1600 A. The longest relaxation, as measured by the line width, gives $T_2=3\mathrm{}\times {10}^{-8\mathrm{}}$ sec. The sample thickness was equal to or less than the skin depth, resulting in a Lorentzian-type line. Multiple resonances were obtained according to shape anisotropy theory.