Effect of epitaxial strain on ferroelectric polarization in multiferroic BiFeO3 films

Journal Article · Tue Jan 01 04:00:00 EST 2008 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.2830799· OSTI ID:975056

Kim, Dae Ho ^[1]; Lee, Ho Nyung ^[1]; Christen, Hans M ^[1]; Biegalski, Michael D ^[1]

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1. 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 Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 975056
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 1 Vol. 92; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
BISMUTH OXIDES
EPITAXY
FERROELECTRIC MATERIALS
IRON OXIDES
NANOSTRUCTURES
POLARIZATION
STRAINS
THIN FILMS