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Author Warren, W. L. ♦ Pike, G. E. ♦ Vanheusden, K. ♦ Dimos, D. ♦ Tuttle, B. A. ♦ Robertson, J.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ FERROELECTRIC MATERIALS ♦ STRAINS ♦ PZT ♦ BARIUM COMPOUNDS ♦ TITANATES ♦ ELECTRON SPIN RESONANCE ♦ POLYCRYSTALS ♦ CRYSTAL DEFECTS ♦ POLARIZATION ♦ HEATING ♦ ELECTRIC DIPOLES ♦ BARIUM TITANATES
Abstract We show the alignment of defect dipoles along the direction of the spontaneous polarization in polycrystalline Pb(Zr,Ti)O{sub 3} and BaTiO{sub 3} ferroelectric ceramics using electron paramagnetic resonance (EPR). The alignment is demonstrated via orientation dependent paramagnetic centers in the polycrystalline materials and computer modeling of the EPR line shapes. It is shown that defect dipoles can become aligned by oxygen vacancy motion in the octahedron about a negatively charged center for the oxygen vacancy-related dipole complexes or by defect displacement and domain realignment in the lattice for isolated defect centers. We find that the alignment is not observed in nonferroelectric materials such as SrTiO{sub 3}, and is destroyed in ferroelectric materials by heating above the Curie temperature. These observations suggest an interplay between distortion in the unit cell and the ability to align defect dipoles, as is the case more generally for ferroelectric dipole alignment. We also directly observe aligned intrinsic Ti and Pb ion displacements in the ferroelectric Pb(Zr,Ti)O{sub 3} perovskite unit cell. {copyright} {ital 1996 American Institute of Physics.}
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-06-01
Publisher Department Sandia National Laboratory
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 79
Issue Number 12
Organization Sandia National Laboratory