Ultra-soft magnetic films: micromagnetism and high frequency properties

The wavelength and amplitude of the longitudinal oscillations of the transversal and longitudinal components of magnetization was obtained from the contrast ripple observed by the Lorentz TEM. The micromagnetic ripple is connected with the internal stray field in the film. The theory, based on Landau-Lifshitz equation, is developed, where the internal stray field is taken into account. The theory predicts that the micromagnetic ripple can broaden the ferromagnetic resonance (FMR) to lower range of the frequencies. For a certain range of the internal stray field a second bump at lower frequencies arrives, which shows up in some previously reported spectra.