Band gap tuning and room temperature ferromagnetism in Co doped Zinc stannate nanostructures

The effect of Co doping on structural, optical and magnetic behavior of pure and Co doped Zinc stannate (ZTO) nanostructures was investigated. Pure and Co (1%, 3% & 5%) doped Zn2SnO4 compounds were prepared through simple precipitation route. Formation of cubic inverse spinel structure and metal oxide vibrations of the samples were investigated using XRD and FTIR. Co doping influences the crystallite size producing micro strain in ZTO lattice. Poly dispersed rod like shape of the particles was examined by FESEM. Elemental composition of prepared samples was identified by EDAX analysis. Optical Absorption spectra shows significant red shift on increasing the dopant concentration which indicates the reduction in optical band gap. Visible luminescence observed from photoluminescence studies confirms the presence of oxygen vacancies and trap sites in the lattice. Magnetization analysis reveals the enhanced ferromagnetic behavior in all Co doped ZTO samples. The amplified ferromagnetic ordering in Co doped ZTO compounds has been explained in terms of defects serving as free spin polarized prophetic carriers.