Volume Dependence of Ferrimagnetic Resonance Properties in Ni1−xCoxFe2O4

A microwave resonance apparatus for measuring $K_1\mathrm{/M}$ , $K_2\mathrm{/M}$ , $g_{\mathrm{eff}}$ , linewidth and magnetization as functions of pressure to 10000 atmos is described. At this pressure the volume of nickel ferrite is reduced by only 0.68% but significant changes in magnetic properties are observed. The results of measurements on ${\mathrm{Ni}}_{\text{1−x}}{\mathrm{Co}}_x{\mathrm{Fe}}_2{\mathrm{O}}_4\text{(x\hspace{0.17em}=\hspace{0.17em}0,\hspace{0.17em}0.05,\hspace{0.17em}0.10)}$ are discussed in terms of Slonczewski's anisotropy theory.