Tertiary Ni0.7-xZn0.3MxFe2O4 (M=Mn, Co, and Cu) spinel ferrites: Electrical and dielectric properties

Three systems of polycrystalline Ni0.7-xZn0.3MxFe2O4 ferrite (M = Mn2+, Co2+, and Cu2+; x = 0.0, 0.1, 0.3, 0.5, and 0.7) have been prepared using the citrate method. The dc conductivity (sigma(dc)), ac conductivity (sigma(ac)), dielectric constant (epsilon'), and dielectric loss (epsilon") of Ni-Zn ferrite doped with Mn/Co/Cu ions have been thoroughly inspected. Variations in dc and ac conductivity for each ferrite series have been evaluated with temperature elevation from 293 up to 848 K and altered frequencies from 10(2) to 10(6) Hz. The conductivity for dc and ac displayed both metallic and semiconductor-like behavior with temperature. The magnitudes of activation energies (E-sigma) are estimated and discussed for the three investigated systems from Arrhenius plots. Small polaron hopping between Fe3+ and Fe2+ ions is accountable for the conduction mechanism in existing systems. Moreover, the behavior of dielectric parameters with increasing Mn/Co/Cu concentrations has been evolved independently. The enhanced values of conductivity, dielectric constant, and small dielectric loss are attained in copper doped Ni-Zn ferrite compositions particularly at high concentrations. This is a very promising feature for high-frequency and power applications of ferrites. (C) 2020 Elsevier B.V. All rights reserved.