Ferrimagnetic resonance low-field effects in rod samples

A previously unreported absorption which is indicated in the curve of the imaginary part of the external permeability of rod-shaped samples is reported. This curve was transformed from intrinsic permeability data obtained from measurements on polycrystalline garnet samples of different densities. This energy absorption revealed in the loss curve of the external permeability occurs in the vicinity of the dc field at which the intrinsic tensor permeability resonates and appears to be affected by the porosity of the material. The phenomenon is more noticeable at L-band frequencies than at S-band frequencies.