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Full Record Details
Persistent URL
http://purl.org/net/epubs/work/51069
Record Status
Checked
Record Id
51069
Title
Effect of local dipole moments on the structure and lattice dynamics of K0.98Li0.02TaO3
Contributors
JS Wen (Brookhaven National Lab. & SUNY Stony Brook)
,
GY Xu (Brookhaven National Lab.)
,
C Stock (STFC Rutherford Appleton Lab.)
,
PM Gehring (NIST Center for Neutron Research)
,
Z Zhong (Brookhaven National Lab.)
,
LA Boatner (ORNL)
,
EL Venturini (Sandia National Labs)
,
GA Samara (Sandia National Labs)
Abstract
We present high-energy x-ray (67 keV) and neutron-scattering measurements on a single crystal of K1-xLixTaO3 for which the Li content (x=0.02) is less than x(c)=0.022, the critical value below which no structural phase transitions have been reported in zero field. While the crystal lattice does remain cubic down to T=10 K under both zero-field and field-cooled (E <= 4 kV/cm) conditions, the Bragg peak intensity changes significantly at T-C=63 K. A strong and frequency-dependent dielectric permittivity is observed at ambient pressure, a defining characteristic of relaxors. However an extensive search for static polar nanoregions, which is also widely associated with relaxor materials, detected no evidence of elastic neutron diffuse scattering between 300 and 10 K. Neutron inelastic scattering methods were used to characterize the transverse acoustic and optic phonons (TA and TO modes) near the (200) and (002) Bragg peaks. The zone-center TO mode softens monotonically with cooling but never reaches zero energy in either zero field or in external electric fields of up to 4 kV/cm. These results are consistent with the behavior expected for a dipolar glass in which the local polar moments are frozen and exhibit no long-range order at low temperatures.
Organisation
ISIS
,
STFC
Keywords
Physics
Funding Information
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Language
English (EN)
Type
Details
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Year
Journal Article
Phys Rev B
78 (2008): 144202.
doi:10.1103/PhysRevB.78.144202
2008
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