Correlation between structural and electrical properties of Mg1−2xZnxNixAl2O4 (x = 0.0–0.5) ceramic nanomaterials synthesized by a urea assisted microwave combustion method

A urea assisted microwave combustion method was used to synthesize Mg1−2xNixZnxAl2O4 (x = 0.0–0.5) ceramic materials. X-ray diffraction (XRD) analysis confirmed the formation of a single spinel phase with an average Scherrer crystallite size of in the range 24–51 nm. The chemical composition of the synthesized compounds was determined by energy dispersive X-ray fluorescence (ED-XRF). The synthesized materials show crystalline morphology as evidenced by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results. Spinel formation was confirmed by the appearance of peaks at 550 and 712 cm−1 in the FTIR spectra. A significant increase in room the temperature (RT) resistivity from 0.27 × 109 to 9.41 × 109 Ω cm was achieved by doping with a binary mixture of Ni–Zn. The dielectric constant (ɛ) and the loss tangent (tan δ) follow the mechanism of space charge polarization. High resistivity, a low dielectric constant and a small loss tangent make the materials suitable for applications as insulators and electromagnetic radiation absorbers in the electronics industry.