Enhanced oxygen defect transport in Ca-doped bismuth ferrite thin films

Understanding defect transport is the cornerstone for a variety of future applications. Ca-doped bismuth ferrite (BCFO) is a promising material for studying collective ion transport because of its unique properties^1-3. We measure the ionic conductivity of BCFO thin film grown on SrTiO₃(100) in both non-destructive and destructive methods. We conduct the electrochemical impedance spectroscopy with different magnitudes of AC voltage to understand the ionic conduction mechanism of BCFO. By using the mixed conductor equivalent circuit model, we obtain ionic conductivity, which shows enhanced conductivities at the low applying electric field. On the other hand, Ionic conductivity of BCFO is visualized with the observation from electroforming experiments with DC voltages. The results from these two different methods show consistency and provides useful insight into the ionic conduction mechanism in solids.

[1] J. S. Lim et al., NPG Asia Materials 10, 943-955, (2018)

[2] H. S. Park et al., Applied Physics Letters 115, 183901, (2019)

[3] J. Suh et al., Applied Physics Letters 119, 022902, (2021)