Abstract
Ferromagnetic resonance measurements have been performed on single‐crystal samples of the hexagonal ferrites BaFe12O19, Zn2Y, and Co2Y. Values of linewidth, g value, and anisotropy field are given as a function of temperature from 77°K to 600°K at various frequencies between 8 and 75 kMc. Zn2Y is singularly interesting because it exhibits an extremely narrow room temperature linewidth at X band. Values as low as 16 oe, with anisotropy fields of 9000 oe are reported. The theory of the resonance behavoir is developed and compared to the experimental results.