Effect of epitaxial strain on ferroelectric polarization in multiferroic BiFeO3 films
- ORNL
Multiferroic BiFeO3 epitaxial films with thickness ranging from 40 nm to 960 nm were grown by pulsed laser deposition on SrTiO3 (001) substrates with SrRuO3 bottom electrodes. X-ray characterization shows that the structure evolves from an angularly-distorted tetragonal structure with c/a 1.04 to a bulk-like rhombohedral structure as the strain relaxes with increasing thickness. Despite this significant structural evolution, the ferroelectric properties barely change: the remanent polarization measured in the [001] direction slightly decreases from 69.2 1 C/cm2 in fully strained to 66.0 1 C/cm2 in fully relaxed films. Assuming a polarization direction along the long body diagonal of the respective distorted pseudo-cubic unit cells, this corresponds to a decrease of only 1.4% as c/a changes from 1.04 to 1.0. This illustrates the difference between the present lone-pair driven mechanism of ferroelectricity and the one observed, for example, in BaTiO3.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 975056
- Journal Information:
- Applied Physics Letters, Vol. 92, Issue 1; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
Similar Records
Large ferroelectric polarization in antiferromagnetic BiFe0.5Cr0.5O3 epitaxial films
Strong polarization enhancement in asymmetric three-component ferroelectric superlattices