Quantum effects and glasslike behavior in ferroelectric oxides

Conference · Sat Aug 01 04:00:00 EDT 1987

OSTI ID:6314024

Samara, G A

Quantum fluctuations, or zero-point motions, can strongly influence the low temperature response of a system near a structural phase transition. Among the manifestations of quantum fluctuations at ferroelectric phase transitions are different critical exponents, the suppression of the transition temperature, T/sub c/, below its classical value and the development of a quantum paraelectric state. To study these quantum effects as well as the crossover from the classical to the quantum regime, it is necessary to shift T/sub c/ continuously from high to low temperatures. Hydrostatic pressure is an excellent variable for doing so. Results on the mixed oxides K/sub 1-y/Na/sub y/TaO/sub 3/ and KTa/sub 1-x/Nb/sub x/O/sub 3/ for fixed y and x wil be summarized and discussed to illustrate some of the essential features. Some of these mixed oxides, as well as oxides, exhibit short-range dipolar correlations and glass-like responses. An important current debate is centered around the question of whether or not the low temperature phase of these systems results from the freezing in of short-range order. Results on KTa/sub 1-x/Nb/sub x/O/sub 3/ oxides will be discussed and contrasted with other oxides. A novel pressure-induced crossover from normal ferroelectric ordering to dipolar glass behavior in soft TO mode systems with dilute impurities will be discussed, and possible experimental evidence for such a phenomenon will be presented.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6314024
• Report Number(s): SAND-87-1031C; CONF-870843-1; ON: DE87012407
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602 -- Other Materials-- Structure & Phase Studies
656001* -- Condensed Matter Physics-- Solid-State Plasma
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYSTALS
DIELECTRIC PROPERTIES
ELECTRICAL PROPERTIES
FERROELECTRIC MATERIALS
FLUCTUATIONS
MECHANICS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POLARIZATION
PRESSURE DEPENDENCE
QUANTUM MECHANICS
VARIATIONS