Relationship Between Thermal Expansion Coefficient and Ionic Conduction in Perovskite-Type Oxides

The thermal expansion coefficient of complex perovskite-type oxides increases with the increase in the oxygen ionic conductivity. In the present study, with the aim to explain such a behavior, a research has been carried out from a chemical bond point of view. The ionicity fiµ of the individual bond µ, A–O and B–O bonds, and the thermal expansion coefficient of A1-xA\u27xB1-yB\u27yO3-δ were estimated theoretically. It is found that the oxygen ionic conductivity and the thermal expansion coefficient decrease with the increase in the difference of ionicity Δfi