Gyromagnetic Ratio of Nickel Ferrite

The gyromagnetic ratio of the ferrite NiO${\mathrm{Fe}}_2$ ${\mathrm{O}}_3$ was determined by measurements of the Einstein-de Haas effect. The $g^{\prime }$ value of 1.849±0.002 indicates that the magnetization is largely due to the ${\mathrm{Ni}}^{++}$ ions as in the Néel model. Comparison with values of $g$ determined by ferromagnetic resonance investigations furnishes evidence as to the validity of the Kittel-Van Vleck relation for ferrites.