Anisotropic pressure dependence of T sub c in single-crystal YBa sub 2 Cu sub 3 O sub 7 via thermal expansion

Journal Article · Fri Jun 01 04:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.41.11299· OSTI ID:7093716

Meingast, C; Blank, B; Buerkle, H; Obst, B; Wolf, T; Wuehl, H ^[1]; Selvamanickam, V; Salama, K ^[2]

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1. Kernforschungszentrum Karlsruhe, Institut fuer Technische Physik, Universitaet Karlsruhe, 7500 Karlsruhe, (Federal Republic of Germany)
2. Texas Center for Superconductivity at the University of Houston, Houston, Texas 77004 (USA)

High-resolution anisotropic-thermal-expansion measurements of single-crystalline and oriented-grained YBa{sub 2}Cu{sub 3}O{sub 7} at the superconducting transition are presented for the first time. Discontinuities in the thermal-expansion coefficient {alpha}{sub {ital a}{ital b}}({Delta}{alpha}{sub {ital a}{ital b}}=(15--23){times}10{sup {minus}8} K{sup {minus}1}), measured with a capacitance dilatometer, are found to occur in both samples. No discontinuity in {alpha}{sub {ital c}}({vert bar}{Delta}{alpha}{sub {ital c}}{vert bar}{lt}1{times}10{sup {minus}8} K{sup {minus}1}) is observed in either sample, although {alpha}{sub {ital c}}({ital T}) shows a distinct change of slope at {ital T}{sub {ital c}}. The specific-heat discontinuity {Delta}{ital C}{sub {ital p}} of both samples was also measured and is used, along with the {Delta}{alpha}'s, to calculate the dependence of {ital T}{sub {ital c}} on uniaxial pressure and uniaxial strain to first order. {ital T}{sub {ital c}} is predicted to increase with pressure applied perpendicular to the {ital c} axis ({ital dT}{sub {ital c}}/{ital dp}{sub {ital a}{ital b}}=0.04--0.09 K/kbar) and to be insensitive to pressure parallel to the {ital c} axis. Uniaxial strain, on the other hand, is found to increase {ital T}{sub {ital c}} about equally in both directions.

• OSTI ID: 7093716
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 41:16; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
656100* -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
ANISOTROPY
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL TEMPERATURE
EXPANSION
HIGH PRESSURE
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
SPECIFIC HEAT
THERMAL EXPANSION
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES