Ferrimagnetic Resonance in Gadolinium Iron Garnet

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