Effect of cobalt doping on structural and thermoelectrical power of zinc allu chromites synthesised by sol–gel auto-combustion method

Abstract

Nanocrystalline cobalt doped zinc allu-chromites (Zn1−xCoxAlCrO4, where x=0.0, 0.25, 0.50, 0.75 and 1.0) were prepared by sol–gel auto-combustion method. These synthesised materials were characterised by XRD, EDAX, SEM, TEM and TEP. XRD pattern shows formation of single cubic spinel phase only. The crystallite size and lattice parameters decrease with increasing cobalt content in zinc allu-chromites. The crystallite size lies in the range between 16 and 21nm. Elemental analysis was carried out by using EDAX. The surface morphology of prepared sample is amorphous in nature which was investigated by SEM. Particle size obtained from TEM analysis was found to be 20nm. The TEP studies of the samples reveal their semiconducting nature which was measured by using two probe methods.