Intrinsic relaxation of the ferromagnetic resonance in substituted yttrium iron garnets

The intrinsic loss properties of the ferromagnetic resonance (FHR) in Ga, Al, Sc and V substituted iron garnets have been investigated at different temperatures from T=77 K up to the Curie temperature by FHR measurements as a function of frequency. After separation of masking two-magnon scattering contributions the intrinsic losses of the bulk single crystal materials were resolved in terms of the dimensionless Landau-Lifshitz damping parameter αf. The results of αf(T) obtained for different temperatures were found to increase linearly versus (T), the reciprocal of the respective saturation magnetization. Apart from the region of magnetic compensation the intrinsic FHR losses for 100 K <T<Tchave been related directly to thermomagnetic properties of substituted YIG using nearly invariant matching parameters.