Impedance spectroscopic analysis of AC response of nanophase ZnO and ZnO-Al2O3 nanocomposites

Nanoparticles of ZnO and Al2O3 were prepared by chemical arrested precipitation. The average panicle size was determined from x-ray line broadening and TEM. The ac electrical response of the consolidated nanoparticles of ZnO and ZnO-Al2O3 nanocomposites was studied using impedance spectroscopic technique. The equivalent circuit parameters were determined by computer simulation. The grain and grain boundary contributions to the conductivity were determined and the difference in the conductivity was attributed to the grain boundary properties of nanomaterials. The variation in conductivity of nanocomposites with weight percentage of Al2O3 was attributed to the change in interfacial defect structure, band structure modifications and compensation of oxygen vacancies. (C) 2000 Acta Metallurgica Inc.