Temperature and frequency dependences of the dielectric properties of YBa sub 2 Cu sub 3 O sub 6+ x ( x approx 0)
- Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185 (USA)
The real ({epsilon}{prime}) and imaginary ({epsilon}{prime}{prime}) parts of the dielectric constant of dense tetragonal ceramic (91--93% of theoretical density) YBa{sub 2}Cu{sub 3}O{sub 6+{ital x}} samples with {ital x}=0.04 and 0.06 were investigated as functions of temperature (4--300 K) and frequency (10{sup 2}--10{sup 6} Hz). At 4K the dielectric loss is very small (tan {delta}{lt}0.005) and {epsilon}{prime}=14.7{plus minus}0.3, independent of frequency. This value of {epsilon}{prime} represents the intrinsic value of the static dielectric constant of the material, i.e., the combined electronic and lattice contributions to {epsilon}{prime}. Both {epsilon}{prime} and {epsilon}{prime}{prime} exhibit small increases with increasing temperature at low temperatures---behavior characteristic of normal dielectrics; however, on further heating strong increases and frequency dispersions develop. Above {similar to}160 K, the {epsilon}{prime}({ital T}) and {epsilon}{prime}{prime}({ital T}) responses are nearly exponential. These temperature and frequency effects are interpreted in terms of dipolar polarization associated with the hopping motion of localized charge carriers. Consistent with this view, the observed frequency dependence of the conductivity is found to obey a power law of the form {sigma}({omega})={ital A}{omega}{sup {ital s}}, where {ital s} is a temperature-dependent constant ({lt}1) and {omega} is the angular frequency. The results can be well represented by Pike's classical hopping model which yields explicitly the {omega}{sup {ital s}} behavior, the temperature dependence of {ital s}, and the energy barrier to the hopping process.
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6973901
- Journal Information:
- Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 41:13; ISSN 0163-1829; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
DIELECTRIC PROPERTIES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FREQUENCY DEPENDENCE
FREQUENCY RANGE
KHZ RANGE
LOW TEMPERATURE
MEDIUM TEMPERATURE
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES