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 (M-s) 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 epsilon', dielectric loss epsilon '', dielectric loss tangent tan delta and ac conductivity, sigma(ac), 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 degrees C. Both dielectric constants (epsilon', epsilon '') found to increase with the increase of the temperature. At low temperatures, dielectric loss tand indicated a decrease with frequency with slight change at high temperatures. (C) 2015 Elsevier B.V. All rights reserved.