Anomalous peak in the thermopower of YBa sub 2 Cu sub 3 O sub 7 minus. delta. single crystals: A possible fluctuation effect

Journal Article · Sun Dec 31 23:00:00 EST 1989 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.41.300· OSTI ID:7008952

Howson, M A ^[1]; Salamon, M B ^[2]; Friedmann, T A; Rice, J P; Ginsberg, D ^[3]

---

1. Department of Physics, University of Leeds, Leeds LS2 9JT, United Kingdom (GB)
2. National Institute of Standards and Technology, Gaithersburg, Maryland 20899 Department of Physics and Materials Research Laboratory, University of Illinois, Urbana-Champaign, Illinois 61801 (USA)
3. Department of Physics and Materials Research Laboratory, University of Illinois, Urbana-Champaign, Illinois 61801 (USA)

We present results for the thermopower of five crystals of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} from the transition temperature {ital T}{sub {ital c}} to 250 K and in magnetic fields to 2 T. The thermopower is approximately {minus}4 {mu}V/K at 250 K for all samples, with a broad phonon drag peak around 150 K. Sharp peaks in the thermopower are observed in the vicinity of {ital T}{sub {ital c}}. The thermopower is qualitatively the same for all crystals except one that was annealed at 650 {degree}C in oxygen. That crystal had a positive thermopower and exhibited no peak at {ital T}{sub {ital c}}. After a reanneal in oxygen at 400 {degree}C, the negative thermopower and peak at {ital T}{sub {ital c}} appeared. We discuss the possibility that the anomalous peak at {ital T}{sub {ital c}} is a fluctuation effect and suggest a simple kinetic argument for the presence of a divergent fluctuation contribution.

• OSTI ID: 7008952
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 41:1; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
ELECTRICAL PROPERTIES
FLUCTUATIONS
HEAT TREATMENTS
LOW TEMPERATURE
MAGNETIC FIELDS
MONOCRYSTALS
ORDER-DISORDER TRANSFORMATIONS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHONONS
PHYSICAL PROPERTIES
QUASI PARTICLES
SCALING LAWS
TEMPERATURE DEPENDENCE
THERMOELECTRIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
VARIATIONS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES