Lattice dynamics and ferroelectric instability in ordered and disordered PbSc{sub 1/2}Ta{sub 1/2}O{sub 3} and PbSc{sub 1/2}Nb{sub 1/2}O{sub 3} solid solutions
- Russian Academy of Sciences, Kirensky Institute of Physics, Siberian Division (Russian Federation)
The dynamic Born charges and the frequency spectra of lattice oscillations in the crystals of ordered and disordered PbSc{sub 1/2}Ta{sub 1/2}O{sub 3} (PST) and PbSc{sub 1/2}Nb{sub 1/2}O{sub 3} (PSN) solid solutions have been calculated within the framework of the generalized Gordon-Kim model with allowance for the dipole and quadrupole polarizabilities. The phonon spectra of both compounds contain ferroelectric soft modes. The influence of various interactions on the magnitude of dynamic charges and ferroelectric instability in PSN and PST solid solutions has been studied and it is shown that both these charges and the ferroelectric instability are determined by the competition between long-range dipole-dipole interactions and short-range dipole-charge interactions, the determining role played by the interaction of Nb (Ta) cations and oxygen anions in the Nb-O (Ta-O) bond direction.
- OSTI ID:
- 21075701
- Journal Information:
- Journal of Experimental and Theoretical Physics, Vol. 105, Issue 3; Other Information: DOI: 10.1134/S1063776107090191; Copyright (c) 2007 Nauka/Interperiodica; Article Copyright (c) 2007 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7761
- Country of Publication:
- United States
- Language:
- English
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