Microwave Resonance in Gadolinium-Iron Garnet Crystals

Ferrimagnetic resonance has been observed in single crystals of gadolinium-iron garnet at 9479 and 23,725 mc. The resonance behavior is discussed in terms of a two-sublattice theory. The gadolinium g-factor is equal to 2.006 above −90°C and increases at lower temperatures. The gadolinium ions contribute to the anisotropy below −40°C. The assignment of separate damping constants to each sublattice explains the sharp variation in over-all damping with temperature near the compensation point.