Electrical conduction and dielectric behaviour of Ge4+-substituted magnesium ferrites

Series of magnesium ferrites with generic formula Mg_1+xGe_xFe_2-2xO₄ were prepared by ceramic method. From XRD studies it is seen that a limited range of x values yields single phase spinel material and only such samples were investigated further. The lattice parameter data was found to be consistent with the ionic size and concentration of the substituent employed. The dc resistivity (ρ) in general was found to increase with x and can be understood on the basis of cation content redistribution on the two sublattices in accordance with the site occupancy preference of the substituent and the magnetic moment data. The activation energies obtained from temperature variation studies in the ferrimagnetic region (below Curie temperature) show a trend similar to that of ρ. The results of dielectric measurements with frequency, and substitutional level are also discussed