Variations of ferroelectric off-centering distortion and 3d-4p orbital mixing in La-doped BiFeO3 multiferroics

Jung Hoon Lee, Hyoung Joon Choi, Dongeun Lee, Min G. Kim, Chung W. Bark, Sangwoo Ryu, Min Ae Oak, Hyun Myung Jang

Research output: Contribution to journalArticle

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Abstract

The lanthanum (La) modification is known to improve dielectric and magnetic properties of BiFeO3 (BFO), a promising room-temperature multiferroic oxide. The effects of La doping on the variations of the off-centering distortion and the orbital mixing of BFO are experimentally studied, in conjunction with first-principles density-functional theory (DFT) calculations. Both the Fe-O bond anisotropy in the FeO6 -octahedron cage and the off-centering ferroelectric polarization along the hexagonal [001] h are predicted to be substantially reduced by the La doping. These DFT predictions agree with the structural-refinement results obtained from high-resolution x-ray powder-diffraction data. We have shown that the apparent improvement of the polarization-field response is not intrinsic and can be attributed to the reduced leakage current by the La doping. X-ray absorption near-edge structure (XANES) spectroscopy study further indicates that the degree of Fe3d-4p orbital mixing decreases with the La doping. The conclusion deduced from XANES study correlates well with the orbital-resolved density of states which predicts that the La doping increases the number of unoccupied states in the p orbital but suppresses the number of unoccupied states in the Fe3d orbital.

Original languageEnglish
Article number045113
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume82
Issue number4
DOIs
Publication statusPublished - 2010 Jul 16

Fingerprint

Lanthanum
lanthanum
Ferroelectric materials
orbitals
Doping (additives)
Density functional theory
Polarization
X ray absorption near edge structure spectroscopy
density functional theory
x rays
X ray absorption
polarization
Leakage currents
Dielectric properties
Oxides
dielectric properties
Magnetic properties
Anisotropy
leakage
magnetic properties

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Lee, Jung Hoon ; Choi, Hyoung Joon ; Lee, Dongeun ; Kim, Min G. ; Bark, Chung W. ; Ryu, Sangwoo ; Oak, Min Ae ; Jang, Hyun Myung. / Variations of ferroelectric off-centering distortion and 3d-4p orbital mixing in La-doped BiFeO3 multiferroics. In: Physical Review B - Condensed Matter and Materials Physics. 2010 ; Vol. 82, No. 4.
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Variations of ferroelectric off-centering distortion and 3d-4p orbital mixing in La-doped BiFeO3 multiferroics. / Lee, Jung Hoon; Choi, Hyoung Joon; Lee, Dongeun; Kim, Min G.; Bark, Chung W.; Ryu, Sangwoo; Oak, Min Ae; Jang, Hyun Myung.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 82, No. 4, 045113, 16.07.2010.

Research output: Contribution to journalArticle

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