Ferromagnetic Resonance in Piezoelectric Ga2−xFexO3

Microwave resonance measurements at 55 kMc and lower frequencies on ${\mathrm{Ga}}_{\text{2−x}}{\mathrm{Fe}}_x{\mathrm{O}}_3$ single crystals which are both ferromagnetic and piezoelectric have been made from room temperature to the Curie point. The crystals exhibit a large orthorhombic anisotropy with easy, intermediate, and hard directions along the orthorhombic $c$ , $a$ , and $b$ axes respectively $\mathrm{(c<a<b)}$ , Linewidths are approximately 1 koe and anisotropy fields approximately 17 koe at room temperature. The origin and representation of the anisotropy is discussed.