Preparation and Some Physical Properties of Zn1−xCrxO

Abstract

A series of Zn1−xCrxO with different Cr concentrations were prepared by solid state reaction. The powders were characterized by X-ray diffractometer and the results exhibited that Cr-doped ZnO consisted of two phases; the major phase was zensite wurtzite structure and the second phase was zinc chromate ZnCr2O4 spinel structure. The results of the Rietveld refinement indicated that the ZnO lattice is further deformed upon Cr substitution. The crystallite size was found to decrease with increasing the Cr substitution, and this may be due to the difference in the ionic radius between Zn2+, and Cr3+, in addition to the segregation of the second phase inhabit the growth mechanism. The calculated energy band gap decreased as Cr concentrations increased. The dielectric properties of Cr doped ZnO were studied in the frequency range 0.1–5 MHz and at different temperatures (30–150 °C). The dielectric constant (e′) and loss factor (tan δ) increased with increasing Cr doping due to the increase of the number of charge carriers and interfacial polarization effects. The conductivity of the samples increases with increasing both of composition parameter x and temperature, and showing semiconducting behavior. The magnetization and the magnetic susceptibility were found to increase with the increase in Cr doping.