抄録
Bismuth titanate (BiT), one of the candidate material for Non-volatile ferroelectric memory, has large spontaneous polarization, but the polarization properties are largely affected by lattice defects. Electrical measurements and first-principles calculations were conducted for BiT to make clear the electrical conduction behavior and to estimate the defect sites of oxygen and bismuth. Oxygen partial pressure dependence of electrical conductivity revealed that BiT single crystals showed oxygen ionic-p-type mixed conduction above 500°C. In particular, both ionic and hole conductivities along the a-axis were very large, indicating that a large amount of oxygen and bismuth defects exist in BiT. The calculations results showed that bismuth in pseudo-perovskite block in BiT was more defective than that in bismuth oxide layer. Possible sites of oxygen defects will also be reported.
