Superconducting energy gap of YBa/sub 2/Cu/sub 3/O/sub 9-//sub delta/ measured by far-infrared reflection

Journal Article · Tue Dec 01 04:00:00 EST 1987 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.36.8802· OSTI ID:5679586

Ye, H; Lu, W; Yu, Z; Shen, X; Miao, B; Cai, Y; Qian, Y

The superconducting energy gap of the high-T/sub c/ superconductor YBa/sub 2/Cu/sub 3/O/sub 9-//sub delta/(T/sub c/ = 90 K) has been measured by the far-infrared technique in the frequency range 30--150 cm/sup -1/ and the temperature range 4.2--200 K. The frequency-dependent reflectances of two different samples show a common feature near ..omega../sub c/approx. =125 cm/sup -1/ where the reflectance curves drop rapidly at very low temperature but are smooth at temperatures larger than 90 K. This indicates that the oxide superconductor YBa/sub 2/Cu/sub 3/O/sub 9-//sub delta/ has a superconducting energy gap 2..delta../sub 0/ = 15.5 meV at very low temperatures and that the ratio 2..delta../sub 0//k/sub B/T/sub c/approx. =2.0 is close to that of superconductors La-Ba-Cu-O and La-Sr-Cu-O, but smaller than the Bardeen-Cooper-Schrieffer theoretical value of 3.5. The temperature dependence of the superconducting energy gap ..delta..(T) is also obtained.

• Research Organization: Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Shanghai, China
• OSTI ID: 5679586
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 36:16; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
BCS THEORY
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ENERGY GAP
FAR INFRARED RADIATION
FREQUENCY DEPENDENCE
FREQUENCY RANGE
INFRARED RADIATION
LOW TEMPERATURE
MHZ RANGE
MHZ RANGE 100-1000
OPTICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIATIONS
REFLECTIVITY
SUPERCONDUCTIVITY
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES