Epitaxial Tl sub 2 CaBa sub 2 Cu sub 2 O sub 8 thin films with low 9. 6 GHz surface resistance at high power and above 77 K

Journal Article · Mon Aug 20 04:00:00 EDT 1990 · Applied Physics Letters; (USA)

DOI:https://doi.org/10.1063/1.104262· OSTI ID:6521539

Hammond, R B; Negrete, G V; Bourne, L C; Strother, D D; Cardona, A H; Eddy, M M ^[1]

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1. Superconductor Technologies Inc., Santa Barbara, CA (USA)

We report measurements of the dc and microwave properties of epitaxial thin films of Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8} on LaAlO{sub 3}. ac magnetic susceptibility measurements yield critical temperatures at the transition midpoint {ital T}{sub {ital c}}{similar to}100 K and 10--90% transition widths of {similar to}1.0 K. We observed a critical current density of 1.06{times}10{sup 6} A/cm{sup 2} at 77 K measured by dc transport. We measured a low-power surface resistance of {ital R}{sub {ital s}}=0.2 m{Omega} at 9.55 GHz and 77 K. This is {similar to}50 times lower than oxygen-free high-conductivity (OFHC) Cu at the same frequency and temperature. At 90 K, {ital R}{sub {ital S}} rises to 0.4 m{Omega}, and at 95 K, {ital R}{sub {ital S}}=0.7 m{Omega}. We measured the microwave power dependence of {ital R}{sub {ital S}} at 77, 90, and 95 K. At high microwave field ({gt}30 G, 77 K) {ital R}{sub {ital s}}=0.8 m{Omega}, more than ten times lower than OFHC Cu.

• OSTI ID: 6521539
• Journal Information: Applied Physics Letters; (USA), Journal Name: Applied Physics Letters; (USA) Vol. 57:8; ISSN APPLA; ISSN 0003-6951
• 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
AMPLIFIERS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL CURRENT
CURRENTS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
EQUIPMENT
FILMS
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
MICROWAVE RADIATION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIATIONS
SUPERCONDUCTING FILMS
SUPERCONDUCTIVITY
THALLIUM COMPOUNDS
THALLIUM OXIDES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE