A study on strontium niobate based piezo-resistive materials for high-temperature and high-pressure sensor applications

Abstract

Perovskite layered structure materials (A2B2O7) exhibit piezo-resistive properties and further it shows a linear trend in electric resistance ≥ 1000 °C, which can be widely used in high-temperature sensors. In this study, (a) strontium niobate (SNO), (b) SNO + 0.03 mol% tungsten trioxide(WO3), (c) SNO + 0.03 mol% cerium dioxide (CeO2) and (d) SNO + 0.03 mol% neodymium(III) oxide (Nd2O3) powders were prepared by the mixed oxide route and calcined at 1250 °C/2 h. The calcined samples were sintered between 1350 and 1450 °C, characterised by X-ray diffraction, scanning electron microscope and electrical resistivity (ρ). In all the cases, DC resistivity followed a linear behaviour from room temperature to 900 °C which decreased from 1014 to 106 Ω cm, respectively, indicating their usefulness for high-temperature sensor applications. Moreover, their piezo-resistive nature was also established and hence, it became suitable for pressure sensor applications. It was observed that the dopants increase the electrical resistivity and decreases the ferroelectric properties as well as the piezo-resistive properties.