Ferrimagnetic resonance has been observed in gadolinium iron garnet from -192° to 72°C. The apparent $g$ factor and line width have their maximum values at the compensation point (13°C). The coincidence of the maximum $g$ with the vanishing of the magnetization implies that the $g$ factors of the ${\mathrm{Gd}}^{+3\mathrm{}}$ and ${\mathrm{Fe}}^{+3\mathrm{}}$ are equal. The temperature dependence of the integrated intensity of the absorption is very similar to that of the magnetization. Below -150°C, both $g$ and the line width increase with decreasing temperature.

• Received 9 May 1957

DOI:https://doi.org/10.1103/PhysRev.107.993