Microwave properties of YBa sub 2 Cu sub 3 O sub 7 minus. delta. high-transition-temperature superconducting thin films measured by the power transmission method

Journal Article · Fri Nov 15 04:00:00 EST 1991 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.350203· OSTI ID:5124687

Miranda, F A; Gordon, W L ^[1]; Bhasin, K B; Heinen, V O; Warner, J D ^[2]

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1. Department of Physics, Case Western Reserve University, Cleveland, Ohio (USA)
2. National Aeronautics and Space Administration, Lewis Research Center, Cleveland, Ohio (USA)

The microwave response of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} superconducting thin films has been studied by performing power transmission measurements. The measurements were made at frequencies within the 26.5--40.0-GHz frequency range, and at temperatures from 20 to 300 K. The films were deposited on LaAlO{sub 3}, MgO, yttria-stabilized zirconia, and LaGaO{sub 3} substrates by laser ablation and dc off-axis magnetron sputtering. From these measurements the complex conductivity {sigma}* = {sigma}{sub 1} {minus} {ital j}{sigma}{sub 2}, the magnetic penetration depth {lambda}, and the surface resistance {ital R}{sub {ital s}} of the films have been determined. It was observed that both {sigma}{sub 1} and {sigma}{sub 2} increased when cooling the films below their transition temperature. This behavior disagreed with that expected from the two-fluid model. In addition, it was observed that the temperature behavior of {sigma}{sub 1} deviates from the predictions of the Bardeen--Cooper--Schrieffer theory. Values of {lambda} have been obtained that are in good agreement with the best reported values for high quality {ital c}-axis-oriented thin films and single crystals ({similar to}140 nm). The anisotropy of {lambda} was determined by measuring this parameter in {ital c}- and {ital a}-axis-oriented films. An intrinsic penetration depth value ({lambda}{similar to}90{plus minus}30 nm) has been estimated from the film thickness dependence of {lambda}. Values of {ital R}{sub {ital s}} for the YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films were calculated and found to be comparable or lower than that of copper at temperatures below 80 K. These {ital R}{sub {ital s}} values were consistent with those found on the same films using resonant-cavity techniques.

• OSTI ID: 5124687
• Journal Information: Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 70:10; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
AMINES
AMMONIUM COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
FILMS
FUNCTIONS
HIGH-TC SUPERCONDUCTORS
MICROWAVE RADIATION
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PENETRATION DEPTH
PHYSICAL PROPERTIES
QUATERNARY COMPOUNDS
RADIATIONS
RESPONSE FUNCTIONS
SUPERCONDUCTING FILMS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES