Conduction of different carriers in (Sr1−xYx)1−zTi1−yFeyO3−δ

The donor or acceptor doped SrTiO₃ with a perovskite structure (ABO₃) has been paid attention as potential candidate materials for oxygen sensors and solid oxide fuel cell. In this work, (Sr_1-xY_x)_1-zTi_1-yFe_yO_3-δ material was fabricated via sol-gel method, and the electronic conductivity and the ionic conductivity of the materials were investigated by ac impedance combining electron-blocking method within 600°950 °C for understanding the conduction of carriers in the materials. The results show that Fe substituted for Ti do not effect on the crystal structure, while Sr is replaced by Y to result obviously the increase of d-spacing of the solid solution. Second, the total electrical conductivity could be fitted well with the Arrhenius formalism at the temperature from 600°C to 900°C, indicating the semi-conductor characters, however the ionic conductivity is not fitted very well. The Fe-doping is favorable for the ionic conduction, while the cation vacancies appear to be not helpful for the ionic conduction in YSTF. The maximal values for the total electrical conductivity are respectively at y=0.5 for Y_0.06Sr_0.94Ti_1-yFe_yO_3-δ and y=0.4 for Y_0.08Sr_0.92Ti_1-yFe_yO_3-δ, and the maximal value of the total electron conductivity is at x = 0.07 for Y_xSr_1-xTi_0.6Fe_0.4O_3-δ.