Magnetic penetration depth measurements of superconducting thin films by a microstrip resonator technique

Journal Article · Mon Jul 01 00:00:00 EDT 1991 · Review of Scientific Instruments; (USA)

DOI:https://doi.org/10.1063/1.1142425· OSTI ID:5810829

Langley, B; Anlage, S M; Pease, R F.W.; Beasley, M R ^[1]

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1. Department of Applied Physics, Stanford University, Stanford, California 94305 (US)

The microstrip resonator technique is a convenient way to sensitively measure the temperature dependence of the magnetic penetration depth, {lambda}({ital T}), in superconducting thin films. Because the method relies on measuring the resonant frequency of a microwave transmission line resonator, one can very precisely measure small changes in {lambda}({ital T}). This technique can resolve changes in {lambda} on the order of several angstroms, allowing a direct measurement of the low-temperature behavior of {lambda}({ital T}), which is a measure of the low-lying pair breaking excitations of the superconductor. Absolute penetration depth values can also be obtained from a self-consistent fit to the data to an assumed temperature dependence. Measurements of the penetration depth of Nb and NbCN film give results that are consistent with the predictions of BCS theory in which 2{Delta}/{ital kT}{sub {ital c}} is treated as an adjustable parameter, while YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films give results that are not completely understood at this time. We also compare this technique with other methods of measuring the penetration depth of superconducting thin films, and discuss the systematic errors present in the measurement.

• OSTI ID: 5810829
• Journal Information: Review of Scientific Instruments; (USA), Vol. 62:7; ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
PENETRATION DEPTH
COPPER OXIDES
HIGH-TC SUPERCONDUCTORS
SUPERCONDUCTING FILMS
YTTRIUM OXIDES
NIOBIUM COMPOUNDS
RESONATORS
TEMPERATURE DEPENDENCE
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
ELECTRONIC EQUIPMENT
EQUIPMENT
FILMS
OXIDES
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties