Synthesis, crystal structure, microstructure and electrical behaviour of systems Sr_1−xLa_xSnO₃ and SrSn_1−xNi_xO₃ (X ≤ 0·10)

Abstract

Undoped and donor doped SrSnO₃ is used as a humidity sensor. The sensitivity increases with increasing donor substitution. Similarly acceptor doped SrSnO₃ has high value of electrical conductivity. In the present investigation, compositions with X ≤ 0·10 were synthesised in the systems Sr_1−xLa_xSnO₃ and SrSn_1−xNi_xO₃ by solid state ceramic route to explore the possible applications as a capacitor or sensor materials. All the compositions were found to form solid solutions and have orthorhombic crystal structure. Average grain size is in the range 0·7–1·2 μm. Densities of all the samples are >90% of the theoretical density. The electrical conduction behaviour of these systems was investigated by the measurement of Seebeck coefficient α and DC conductivity in the temperature range 300–1100 K. These materials exhibit p type semiconduction. Conduction occurs by diffusion of doubly positively charged oxygen vacancies. Electrical resistivity of all these three compositions is very high up to 300°C. These materials may be used as capacitor materials over a considerable range of temperature above room temperature.

Keywords:

• PEROVSKITE
• STRONTIUM STANNATE
• ELECTRICAL CONDUCTIVITY