Specific-heat anomaly near T sub c of the (Bi,Pb)-Sr-Ca-Cu-O superconductor ( T sub c =107 K)

Journal Article · Thu Mar 01 04:00:00 EST 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.41.4296· OSTI ID:6925575

Okazaki, N; Hasegawa, T; Kishio, K; Kitazawa, K ^[1]; Kishi, A ^[2]; Ikeda, Y; Takano, M ^[3]

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1. Department of Industrial Chemistry, Faculty of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan (JP)
2. Sinku-Riko Inc., Midori-ku, Yokohama 226, Japan (JP)
3. Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611, Japan (JP) Oda, K. Kitaguchi, H. Takada, J. Miura, Y. (Department of Applied Chemistry, Faculty of Engineering, Okayama University, Okayama 710, Japan (JP))

Specific-heat measurements of the 107-K phase of the (Bi,Pb)-Sr-Ca-Cu-O system were made in the temperature range 80--250 K by an ac calorimetry method. A finite specific-heat jump at {ital T}{sub {ital c}} ({Delta}{ital C}{sub {ital p}}/{ital T}{sub {ital c}}=16 mJ mol{sup {minus}1} K{sup {minus}2}) was first detected, from which the electronic specific-heat coefficient was calculated through the BCS relationship, i.e., 11 mJ mol{sup {minus}1} K{sup {minus}2}, corresponding to the density of states {ital N}(0)=0.8 states eV{sup {minus}1} (Cu atom){sup {minus}1} spin{sup {minus}1}. This {ital N}(0) value was rather smaller than that of (La{sub 1{minus}{ital x}}M{sub {ital x}}){sub 2}CuO{sub 4} ({ital M}=Sr,Ca) or Ba{sub 2}YCu{sub 3}O{sub 7}. This is in contrast with the usually observed positive correlation between {ital T}{sub {ital c}} and {ital N}(0) among the conventional metallic superconductors. A broadened transition width and the sharpened peak at {ital T}{sub {ital c}} observed in the {ital C}{sub {ital p}}--{ital T} curve was attributed to the two-dimensional superconducting fluctuation effect with coherence length {xi}(0)=13 {ital A} in the plane.

• OSTI ID: 6925575
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 41:7; ISSN 0163-1829; ISSN PRBMD
• 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
BCS THEORY
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COHERENCE LENGTH
COPPER COMPOUNDS
COPPER OXIDES
DIAGRAMS
DIMENSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ENERGY-LEVEL DENSITY
FLUCTUATIONS
LEAD COMPOUNDS
LEAD OXIDES
LENGTH
LOW TEMPERATURE
OXIDES
OXYGEN COMPOUNDS
PHASE DIAGRAMS
PHYSICAL PROPERTIES
SPECIFIC HEAT
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
VARIATIONS