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

¹Centre of Material Sciences, University of Allahabad, Prayagraj 211002, India

²Department of Physics, Banasthali Vidyapith, Banasthali 304022, India

Adv. Mater. Lett., 2021, 12 (3), 21031611

DOI: 10.5185/amlett.2021.031611

Publication Date (Web): Dec 10, 2020

Copyright © IAAM-VBRI Press

E-mail: mksingh100@yahoo.com (MKS); upendra.bhu512@gmail.com (UK)

Abstract

Single phase sample of CaSnO₃ and Ca_0.98Nd_0.02Sn_0.98Ti_0.02O₃ were synthesized by sol-gel route followed by calcination at 800^oC. 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 Nd³⁺ state below conduction band. The dielectric constant of both samples (30 and 18) was found to be temperature independent up to 220^oC and 300^oC 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 activation energy is reflected an electronic as well as mixed ionic and electronic conduction in samples. Based on these studies, the present material can be used in UV-filter, sensors, and mixed ionic and electronic conductor applications.

Keywords

Perovskite CaSnO_3, Rietveld refinement, Reflectance spectroscopy, Dielectric properties, Arrhenius conduction.