Polarization and lattice strains in epitaxial BaTiO{sub 3} films grown by high-pressure sputtering

Journal Article · Fri Jun 01 04:00:00 EDT 2007 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2745277· OSTI ID:20979419

Petraru, A; Pertsev, N A; Kohlstedt, H; Poppe, U; Waser, R; Solbach, A; Klemradt, U ^[1]

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1. Institut fuer Festkoerperforschung and CNI, Forschungszentrum Juelich, D-52425 Juelich (Germany)

High-quality BaTiO{sub 3} films with thicknesses ranging from 2.9 to 175 nm were grown epitaxially on SrRuO{sub 3}-covered (001)-oriented SrTiO{sub 3} substrates by high-pressure sputtering. The crystal structure of these films was studied by conventional and synchrotron x-ray diffraction. The in-plane and out-of-plane lattice parameters were determined as a function of film thickness by x-ray reciprocal space mapping around the asymmetric (103) Bragg reflection. BaTiO{sub 3} films were found to be fully strained by the SrTiO{sub 3} substrate up to a thickness of about 30 nm. Ferroelectric capacitors were then fabricated by depositing SrRuO{sub 3} top electrodes, and the polarization-voltage hysteresis loops were recorded at the frequencies 1-30 kHz. The observed thickness effect on the lattice parameters and polarization in BaTiO{sub 3} films was analyzed in the light of strain and depolarizing-field effects using the nonlinear thermodynamics theory. The theoretical predictions are in reasonable agreement with the measured thickness dependences, although the maximum experimental values of the spontaneous polarization and the out-of-plane lattice parameter exceed the theoretical estimates (43 {mu}C/cm{sup 2} vs 35 {mu}C/cm{sup 2} and 4.166 A vs 4.143 A). Possible origins of the revealed discrepancy between theory and experiment are discussed.

• OSTI ID: 20979419
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 101; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM COMPOUNDS
BRAGG REFLECTION
CAPACITORS
CRYSTAL STRUCTURE
DEPOSITION
ELECTRIC POTENTIAL
ELECTRODES
EPITAXY
FERROELECTRIC MATERIALS
HYSTERESIS
KHZ RANGE 01-100
LATTICE PARAMETERS
POLARIZATION
RUBIDIUM OXIDES
SPUTTERING
STRONTIUM TITANATES
SUBSTRATES
THIN FILMS
X RADIATION
X-RAY DIFFRACTION