The spinel ferrite of compositions (Ni0.2Mg0.8-ZnxFe2O4)-Zn-x (x = 0.2, 0.4, 0.6, 0.8) are synthesized using microwave double sintering technique. X-ray diffraction study reveals formation of single phase spinel cubic structure. The lattice parameter (a), average crystallite size (D) and bulk density (rho(b)) are increasing with zinc content. Fourier-transform infrared spectra are recorded to locate octahedral and tetrahedral sites. The dielectric constant (epsilon(r)), loss tangent (tan delta), ac, dc-electrical conductivities (sigma(ac) and sigma(dc)) are increasing while Curie transition temperature (T-c) and activation energies (E-a) are decreasing with zinc substitution. Power law fit is applied to logo versus logo omega plots to evaluate dc-electrical conductivity and exponent (n) at room temperature. Electrical conduction mechanism and relaxation time (tau) are reported from impedance analysis. Hysteresis loop attributes that saturation magnetization (M-s), anisotropy constant (K-1) and coercivity (H-c) are decreasing with substituent. Low coercivity of 1.96-2.89 G obtained is suitable for magnetic recording applications. (C) 2016 Elsevier B.V. All rights reserved.