SOFT MODE ANOMALIES IN THE PEROVSKITE RELAXOR Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}
Neutron inelastic scattering measurements of the polar TO phonon mode in the cubic relaxor Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}, at room temperature, reveal anomalous behavior similar to that recently observed in Pb(Zn{sub 1/3}Nb{sub 2/3}){sub 0.92}Ti{sub 0.08}O{sub 3} in which the optic branch appears to drop precipitously into the acoustic branch at a finite value of the momentum transfer q = 0.2 {angstrom}{sub {minus}1}, measured from the zone center. By contrast, a recent neutron study indicates that PMN exhibits a normal TO phonon dispersion at 800 K. The authors speculate this behavior is common to all relaxor materials, and is the result of the presence of nanometer-scale polarized domains in the crystal that form below a temperature T{sub d}, which effectively prevent the propagation of long wavelength (q = 0) phonons.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 755043
- Report Number(s):
- BNL-67270; KC020201; R&D Project: PO010; KC020201; TRN: US0005129
- Resource Relation:
- Conference: WORKSHOP ON FERROELECTRICS, ASPEN, CO (US), 02/14/2000--02/19/2000; Other Information: PBD: 9 Mar 2000
- Country of Publication:
- United States
- Language:
- English
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