Investigation of magnetic bubble films using spin wave and magnetoelastic resonances

The FMR spectra of magnetic bubble films have been measured in the low frequency microwave range and the frequencies at which the magnetoelastic excitation of elastic resonances vanishes have been determined. From these data the regions where localized modes are concentrated have been derived. The observed behaviour of the modes is a consequence of the spatial variation of the uniaxial anisotropy, which differs markedly for films grown by the vertical or the horizontal dipping method. Spatial variations of the anisotropy field are predicted which qualitatively can explain the experimental results as shown by numerical calculations.