Click here to view fulltext PDF

Permanent link:
https://www.ias.ac.in/article/fulltext/boms/036/06/1019-1036

Ceramics; oxides; infrared spectroscopy; electrical properties; electrical conductivity.

Polycrystalline powder of BaSnO₃ was prepared at 1300 °C using a high-temperature solid-state reaction technique. X-ray diffraction analysis indicated the formation of a single-phase cubic structure with lattice parameter: 𝑎 = (4.1158 ± 0.0003) Å. The synthesized powder was characterized using X-ray diffraction (XRD) scanning electron micrographs, energy dispersive X-ray analysis, differential thermal analysis, thermogravimetric analysis and Fourier transform infrared techniques. Electrical properties were studied using a.c. impedance spectroscopy technique in the temperature range of 50–650 °C and frequency range of 10 Hz–13 MHz. The complex impedance plots at temperature ≥ 300 °C show that total impedance is due to the contributions of grains, grain boundaries and electrode. Resistance of these contributions has been determined. Variation of these resistances with temperature shows the presence of two different regions with different slopes. The nature of variation for the above three resistances, in both the temperature regions confirms that conducting species (phases) responsible for grain, grain boundaries and electrode are the same. Based on the value of activation energy, it is proposed that conduction via hopping of doubly ionized oxygen vacancies ($V^{\bullet \bullet}_{o}$) is taking place in the temperature region of 300–450 °C, whereas in the temperature region of 450–650 °C, hopping of proton, i.e. OH$^{\bullet}$ ions occurs.

Shail Upadhyay¹

1. Department of Physics, Institute of Technology, Banaras Hindu University, Varanasi 221 005, India

Published

November 2013

Manuscript received

29 May 2012

Manuscript revised

14 July 2012