Some physical properties of Mg-Zn ferrites

Electric, dielectric, and structural studies were carried out at room temperature for a series of MgxZn1-xFe2O4 ferrite samples prepared by the usual ceramic technique. The experimental results showed that the real dielectric constant ε′ and dielectric loss factor tan δ decrease whereas the ac electrical conductivity σ2 (ω, T) increases on increasing the angular frequency ω. The dc and ac electrical conductivities, real dielectric constant, and dielectric loss factor were found to decrease with increasing Mg ion substitution. The parameters n and B in the power law σ2 (ω, T) = Bωn for the electrical conductivity σ2 (ω, T) were found to be composition dependent, with both n and B decreasing as the Mg ion addition increased. According to the experimental results, empirical formulae are suggested for the composition dependences of the electrical conductivity σ and the parameters n and B. The analysis of X-ray diffraction patterns showed that the samples investigated have a single phase cubic spinel structure. The bulk and theoretical density, lattice constant, and radius of the tetrahedral ion decrease whereas porosity increases as Mg ion substitution increases. The infrared absorption spectra showed three of the characteristic bands for ferrites with intensities and positions (wavenumbers) that are composition dependent. The fourth band of the infrared spectra ν4, related to the lattice vibrations, was too weak to be observed at room temperature.