Structural, magnetic and dielectric studies of copper substituted nano-crystalline spinel magnesium zinc ferrite

Nano-crystalline Mg0.5Zn0.5−xCuxFe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) ferrite powders were synthesized using co-precipitation method. The influence of Cu2+ ions substitution on the structural and magnetic properties was investigated. X-ray diffraction measurements revealed the formation of nano-crystalline ferrite with single cubic spinel phase. The lattice constant was found to decrease with increasing Cu2+ ions content. Infrared spectral analysis confirmed formation of the spinel structure for the respective ferrite system. Magnetic data showed that the saturation magnetization (Ms) increases with Cu2+ concentration up to x = 0.2 and then decreases with further increase of Cu2+ ions in this ferrite system. The proposed cation distribution deduced from X-ray diffraction, infrared spectra and magnetization data indicated mixed ferrite type. Dielectric constants ε′, dielectric loss ε′′, dielectric loss tangent tan δ and ac conductivity, σac, were investigated as a function of frequency and temperature. Influence of Cu2+ substation on the ac conductivity exhibited significant behavior at low frequencies and low temperatures, T ⩽ 100 °C. Both dielectric constants (ε′, ε″) found to increase with the increase of the temperature. At low temperatures, dielectric loss tan δ indicated a decrease with frequency with slight change at high temperatures.