Solid-state reaction synthesis and electrical properties of Sm0.9Sr0.1AlO3-δ perovskite oxide

The Sm0.9Sr0.1 AlO3-delta samples were prepared by solid-state reaction. Their microstructure, morphology, electrical properties and transport mechanism were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), alternating current impedance technology and oxygen concentration cell method, respectively. The relationship between sintering technology, relative density and conductivity was studied. The experimental results show that the Sm-0.9 Sr-0.1 AlO3-delta perovskite oxides with single tetragonal phase can be obtained when they are sintered at 165 degrees C. Among all the samples, Sm-0.9 Sr-0.1 AlO3-delta sample sintered at 1650 degrees C for 16 h has the highest relative density of 96. 7 % and electrical conductivity of 1.3 x 10(-2) S/cm at 900 degrees C. The curves of In(sigma T) against 1000/T reveal two straight lines intersecting at 670 degrees C, showing the activation energy of conduction in the high temperature range( T > 670 degrees C) is lower than that in the low temperature range(T < 670 degrees C). Sm-0.9 Sr-0.1 AlO3-delta is a mixed conductor of oxygen ion and hole in air. Its oxygen ionic transference number is around 0.7 in the measuring temperature region, and slightly increases with increasing temperature. By means of oxygen ionic transference numbers measured in air, the relative contributions of ionic and electronic conduction are separated, and the results reveal that activation energy for oxygen ionic conduction of 0.95 eV is lager than that for hole conduction of 0.84 eV, and Sm-0.9 Sr-0.1 A1O(3-delta) has an oxygen ionic conductivity of 9.65 x 10(-3) S/cm at 900 degrees C.