Structural, Optical and Electrical Properties of CaSnO3 and Ca0.98Nd0.02Sn0.98Ti0.02O3 Synthesized using Sol-Gel Method

Single phase sample of CaSnO3 and Ca0.98Nd0.02Sn0.98Ti0.02O3 were synthesized by sol-gel route followed by calcination at 800 o C. The X-ray diffraction pattern of both samples showed monophasic, and their Rietveld refinement studies indicated that the samples belonged to orthorhombic crystal structure under space group Pbnm. Moreover, dopant substitution results in unit cell compression due to lower ionic radii of dopant than host. UV-Vis. spectroscopy study of samples reflected semiconducting samples. The direct optical band gap of doped sample found smaller (4.02 eV) than undoped (4.23 eV), due to formation of Nd 3+ state below conduction band. The dielectric constant of both samples (30 and 18) was found to be temperature independent up to 220 o C and 300 o C and tangent loss below 1 makes it suitable candidate for thermally stable capacitor application. Ac conductivity of samples was analyzed using Arrhenius model as a function of frequency and temperature, and the value of activa