Effect of the substrate on the ferromagnetic resonance linewidth in barium ferrite films

A theory for the interaction of a ferrite film on a substrate with the short-circuit waveguide field has been developed. The relations explaining the effect of the substrate on the parameters of resonant absorption of the energy of the exciting field have been derived. The results of analysis of ferromagnetic resonance in barium ferrite films are presented. The films prepared in a special way have the shape of small disks on rectangular substrates. It is found that the width of the resonance curve noticeably depends on the disk diameter.