Ferromagnetic Resonance in the Highly Anisotropic Ferrimagnet Gallium Iron Oxide

Resonance measurements at 70 Gc/sec have been made on single crystals of Ga_2-xFeₓO₃ (x1.1) in the temperature range from 1.2 to 360^∘{}K. The resonance spectra of this complex and highly anisotropic ferrimagnet can be fitted using three parameters. In the range above 200^∘{}K the g value was found to be 1.94±{}0.04, with an asymptotic value of 1.96 at high temperatures. At 4.2^∘{}K the anisotropy fields are 31 and 58 kG along the intermediate and hard magnetic axes, respectively. The same parameters fit the low-field resonance modes where M and H are not parallel, and thus confirm the above values. The observed linewidths are large and anisotropic, varying from approximately 400 to 2400 G.