Title: Strain enhanced ferroelectric properties of multiferroic BiFeO3/SrTiO3 superlattice structure prepared by radio frequency magnetron sputtering
Authors: Chiu, Shang-Jui
Liu, Yen-Ting
Lee, Hsin-Yi
Yu, Ge-Ping
Huang, Jia-Hong
Master and Ph.D. Program for Science and Technology of Accelrrator Light Source
Keywords: Superlattice structures;Interfacial strain;Radio-frequency sputtering;Bismuth ferrite
Issue Date: 31-Jul-2013
Abstract: Asymmetric superlattice structures consisting of SrTiO3 (STO) and multiferroic BiFeO3 (BFO) sublayers were deposited on a Nb-doped STO (001) substrate with a radio frequency magnetron sputtering system. For an investigation of the effect of strain on the microstructures, ferroelectric properties and piezoelectric properties resulting from a difference of lattice parameters of the BFO sublayer, varying the thickness of the STO sublayer in a range 1-2.5 nm introduced interfacial strain into the superlattice. The epitaxial relation and strain state of films were clearly observed with a synchrotron as a source of radiation. The results of X-ray diffraction measurements clearly showed that the decrease of strain was related to the thickness of the STO substrate. A separate diffraction signal of the superlattice structure with thickness >= 1.75 nm of the STO sublayer was found, indicating a large strain relaxation in these superlattice films. The remnant polarization values P-r, piezoelectric coefficient d(33) and leakage properties of the BFO/STO superlattice thin films that improved with increasing in-plane strain provide strong evidence of a strain-enhancement effect. The BFO/STO superlattice with a well defined crystal structure and a large strain state showed a large P-r, greater than a BFO single layer of the same thickness. (C) 2013 Elsevier B.V. All rights reserved.
URI: http://dx.doi.org/10.1016/j.tsf.2013.05.004
ISSN: 0040-6090
DOI: 10.1016/j.tsf.2013.05.004
Volume: 539
Begin Page: 75
End Page: 80
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