THICKNESS DEPENDENCE OF AUTO OSCILLATIONS IN CIRCULAR YTTRIUM-IRON-GARNET FILMS

Using high-power ferromagnetic resonance the dependence of the auto-os cillation frequency has been investigated as a function of the thickne ss of thin circular yttrium-iron-garnet films. For thicknesses over th e range from 0.5 to 1.4 mu m, the auto-oscillation frequencies are fou nd to be directly proportional to the thickness of the films, even tho ugh the linewidth remains nearly unchanged-over this range. These resu lts indicate that the auto-oscillation frequency is determined by a ma gnetostatic mode spacing. The experimental results are compared with n umerical calculations, based on a microscopic Hamiltonian and show goo d agreement (within 10% for first finger) with the experimental data. (C) 1997 American Institute of Physics.