Preparation, electrical and gas-sensing properties of perovskite-type La1−xMgxFeO3 semiconductor materials

The La1−xMgxFeO3 powder was prepared by sol–gel method using citric acid. The compounds crystallized were perovskite phase with orthorhombic structure. The Mg-doping restrains the growth of the grain size. The conductivity and gas sensing of La1−xMgx FeO3-based sensors were investigated. We found the La0.92Mg0.08 FeO3-based sensors have the best response and selectivity to ethanol gas. Great differences on the conductance–temperature curves of La0.92Mg0.08 FeO3-based sensors between in ethanol gas and air or other gas such as H2, CO and CH4 were also found. The conductance in ethanol gas decreased with temperature from 130 to 240 °C. But in air and other gas such as H2, CO and CH4 the conductance increases all the time. It indicates that at 240 °C the conductance difference between air and ethanol was the biggest and the response reach the maximum.