Temperature dependence of dielectric properties for copper doped magnetite

摘要: Samples with the chemical formula CuxFe3−xO4+δ (x = 0.2, 0.4, 0.6, 0.8, 1 and 0 ≤ δ 0.4; 0.5–0.5x) were prepared by standard ceramic method. The ac conductivity (σac) dielectric loss tangent (tan δ) are measured. Both constant (e � ) �� calculated in temperature range from room up to 773 K at different fixed frequencies. measurements showed that increases both frequency becomes frequency-independent high temperatures. An abnormal behaviour was observed for curves. increase e increasing is ascribed thermal energy given system allows more dipoles be free field orient them its direction. tan curves exhibits a relaxation peaks. first peak assigned copper-ferrite phase transition (tetragonal–cubic) other ferromagnetic (Curie temperature). It second shifted towards lower values frequency. FD as increases. activation ED generally Cu 2+ ion substitution