MAGNETIC-ANISOTROPY AND SPIN DYNAMICS IN AMORPHOUS THIN FERROMAGNETIC-FILMS

An analytic calculation of the initial permeability frequency spectra using the LANDAU-LIFSHITZ theory is compared with experimental results obtained on ferromagnetic thin films with an in-plane uniaxial magnet ic anisotropy. Agreement between the theoretical and the experimental results may not be very good. This may be due to magnetic anisotropy d ispersion in the film. This dispersion is studied and seems to be due to magnetic ripples. Measurement of the ripple effect is done through the measurement of the transverse biased susceptibility and compared w ith theoretical results obtained with the HOFFMANN theory of ripples.