Structural, electrical and dielectric properties of spinel type MgAl2O4 nanocrystalline ceramic particles synthesized by the gel-combustion method

Nanocrystalline spinel type magnesium aluminate (MgAl2O4) ceramic material was synthesized by gel-combustion method. The structural, microstructural, morphology, electrical and dielectric properties of the prepared spinel type MgAl2O4 ceramic material were studied by different techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDX), surface area analyzer (BET) and impedance spectroscopy. The X-ray diffraction pattern and IR spectrum of magnesium aluminate material confirm the formation of impurity free nanocrystalline phase with spinel structure. The specific surface area calculated from the 1/[W((Po/P)−1)] vs relative pressure (P/Po) plot of the annealed MgAl2O4 powder is found to be 162.704 m2/g. The temperature dependent conductivity of nanocrystalline MgAl2O4 pellet was studied and the conductivity of nanocrystalline MgAl2O4 pellet at 573 K is found to be 4.9213×10–13 S cm−1. The activation energies were evaluated from log σT vs 1000/T plot of the observed two different temperature dependent conductivity regions of the nanocrystalline MgAl2O4 sample and are found to be E1=0.1828 eV (<503 K) and E2=0.8791 eV (>503 K).