Mössbauer-effect studies on the magnetic properties of the Ni-Zn—ferrite system

The nickel-zinc—ferrite system ${\left(\mathrm{Zn}\right)}_x{\left(\mathrm{Ni}\right)}_{1-x}{\mathrm{Fe}}_2{\mathrm{O}}_4$, $0.20\le x\le 0.75$, has been studied by means of the Mössbauer effect. The spectra taken at temperatures near and below the Néel temperature were explained by using the perturbation theory of relaxation line shapes for magnetically ordered systems. As the results of the fitting of the experimental spectrum, the average spins and the longitudinal relaxation rates of both $A$- and $B$-site ferric ions were obtained. Their temperature and zinc-content dependences were investigated and explained qualitatively. It was suggested that the dominant relaxation mechanism involves the modulation of the anisotropic part of the $A-O-B$ superexchange interaction.