Dielectric properties of Cu substituted Ni0.5−xZn0.3Mg0.2Fe2O4 ferrites

Abstract Dielectric properties of Cu substituted Ni–Zn–Mg ferrite samples having the general formula Ni 0.5− x Cu x Zn 0.3 Mg 0.2 Fe 2 O 4 (where x  = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) synthesized by Pramanik method are reported. The single phase formation of the ferrites was confirmed by XRD technique. The lattice parameter is found to increase with increase in Cu content. Average grain size, obtained from SEM micrographs, is found to increase with increase in Cu content. Dielectric parameters were measured as a function of frequency at room temperature as well as at higher temperatures. The variation in dielectric constant ( ɛ ′) with temperature at four different fixed frequencies viz. 1 kHz, 10 kHz, 100 kHz, and 1 MHz was also studied. The room temperature dielectric constant ( ɛ ′) and dielectric loss (tan  δ ) are found to decrease with increase in frequency. The ac conductivity ( σ ac ) is found to increase with increase in the frequency.