Optical and transport properties of Sn-doped ZnMn2O4 prepared by sol-gel method

The paper describes the effect of ZnMn2O4 doping with different Sn ratios. Snx-ZnMn2O4 is prepared with Sol-Gel route at 700 °C. The structural, optical and electrical properties were studied. The X-ray diffraction patterns indicate the formation of pure tetragonal phase for the ratios lower than 0.03%, while for other compositions, the secondary phases were observed. The attenuated total reflectance (ATR) analysis confirmed the localization of Sn in octahedral sites. The optical properties showed not only the increase of Eg, but also the improvement of the optical characteristics such as extinction coefficient (k), optical conductivity (σopt), dissipation factor (tan δ) and the relaxation time (τ). The latter has been improved by 50%. The Hall measurements confirmed the transition of the conductivity mode, i.e, from p to n-type. The formation of SnMn1+ point defects is evidenced; however, the transport properties indicate that the charge carriers are mainly localized.