Abstract
The stability of the “T-like” (T$) phase in BiFeO3 films grown on LaAlO3(001) is investigated. We show that the T$ phase can be stabilized for thicknesses >70nm under ultralow incident flux conditions in pulsed laser ablation growth. This low flux results in a low growth rate; thus, the sample is held at high temperatures (>600°C) for much longer than is typical. Transmission electron microscopy and X-ray diffraction analysis suggest that such growth conditions favor the formation of nanoscale “defect pockets”, which apply a local compressive strain of >1.8%. We propose that the cumulative effect of local stresses induced by such “designer defects” maintains macroscale strain coherence mechanical boundary conditions, which then preserves the T$ phase to thicknesses beyond conventional wisdom. Finally, by intentionally introducing an amorphous phase at the film-substrate interface, it is shown that the mixed-phase proportion can be tuned for a given thickness.
| Original language | English |
|---|---|
| Article number | 0902B2 |
| Journal | Japanese Journal of Applied Physics |
| Volume | 57 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 2018 |
Funding
We wish to thank Brahim Dkhil for fruitful discussions. This work was funded by an ARC discovery project. This experiment also used equipment funded by the Australian Research Council (ARC) - Linkage, Infrastructure, Equipment and Facilities grant (LIEF-LE120100104) located at the University of Wollongong Electron Microscopy Centre. The research at Monash Centre for Electron Microscopy (MCEM) used equipment funded by Australian Research Council Grant No. LE0454166 (FEI Titan 80-300 FEGTEM). We thank MCEM for the provision of equipment and technical support. We wish to thank Brahim Dkhil for fruitful discussions. This work was funded by an ARC discovery project. This experiment also used equipment funded by the Australian Research Council (ARC) — Linkage, Infrastructure, Equipment and Facilities grant (LIEF-LE120100104) located at the University of Wollongong Electron Microscopy Centre. The research at Monash Centre for Electron Microscopy (MCEM) used equipment funded by Australian Research Council Grant No. LE0454166 (FEI Titan 80-300 FEGTEM). We thank MCEM for the provision of equipment and technical support.