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The radial oscillation of bubble lattices in LPE garnet films has been measured as a function of static fields applied perpendicular to the film or in the film plane, using a simple RF technique. While the dependence of the measured resonance frequency on the normal field can be described by theory, the measured frequency increases more rapidly with the in-plane field than calculated; this discrepancy is probably due to an incorrect theoretical dependence of the wall mass on the in-plane field.

Magnetoelastic excitations with a fine structure in the 50kHz range have been observed in the study of the domain wall resonance (DWR) in magnetic garnet thin films. DWR excites standing transverse elastic waves which have a resonance frequency given by f= nv 2d , where f is the frequency, n is an integer, v=3.5×10 5 cm/sec is the transversal velocity of the elastic wave, and d=0.05 cm is thickness of the film/substrate system. A fine structure associated with each of these modes has been identified as due to two dimensional bulk elastic waves by using a set of parallel microstrip lines. The dispersion relation of these elastic waves is ω 2 = v 2 ( k 2 1 + k 2 2 ), where ω is the radial frequency, k 1 and k 2 are the wave vectors in the orientation perpendicular and parallel to the sample surface respectively. In the case of k 1 ⪢k 2 , f= f 0 +v 2 k 2 2 f 0 , where f 0 is the resonance when k 2 =0. The experimental results are in excellent agreement with this model. A linear dispersion, observed when using a shorted slot-line structure, is understood as the excitation of three dimensional modes due to the complex structure of the slot-line and the sample geometry.

The infrared absorption of H-ions in LiF and H- and D-ions in NaF has been measured. The energetic positions of the local modes in NaF:D- and LiF:H- allow 2-phonon decay processes as indicated by the variation of the absorption bandwidth at low temperatures. In NaF side bands have been observed.