Crystal and magnetic structures of granular powder spinel Mn–Zn- and Ni–Zn ferrites

Some specific features of the crystal and magnetic structures of granular powder spinel-like ferrites Mn$_{0.160}$Mg$_{0.404}$Zn$_{0.448}$Fe$_{2}$O$_{4}$, Mn$_{0.676}$Zn$_{0.227}$Fe$_{0.09}$Fe$_{2}$O$_{4}$, Mn$_{0.5792}$Zn$_{0.2597}$Fe$_{0.1612}$Fe$_{2}$O$_{4}$, and Ni$_{0.32}$Zn$_{0.68}$Fe$_{2}$O$_{4}$ have been studied by neutron diffraction. It has been established that the crystal structure of all the studied compounds has a cubic symmetry with space group $Fd\bar3m$. Ferrimagnetic ordering is observed in all the studied structures. Based on the experimental data, the unit cell parameters and interatomic bond lengths of the studied compounds are determined alongside with the distribution of cations between octahedral and tetrahedral crystallographic positions in their cubic crystal structure. Corresponding average magnetic moments are calculated for different positions in their cubic structure. Some structural mechanisms of the formation of magnetic properties depending on the level of doping and the size of powder grains are discussed.