Short-range order-long range order in superconducting materials. Final scientific report, 1 October 1980-30 September 1984

Technical Report · Mon Nov 05 04:00:00 EST 1984

OSTI ID:5999337

Levy, M

Surface waves propagating through NbN films which are columnar in nature and which therefore may behave like inhomogeneous two-dimensional superconductors with localized electronic states show attenuation curves which yield an effective superconducting energy gap which saturates at about one third the usual value. A model has been proposed that ascribes this order parameter reduction to the localization of electronic states in the columnar regions. The piezoelectrically induced attenuation curve in a superconducting NbN film is shifted by almost 5 K below the resistivity curve of the film. This shift may be attributed to the resistance in the cores of the Kosterlitz-Thouless vortex-antivortex flux pairs which may exist in an inhomogeneous superconductor. A superconducting granular lead film has been investigated with surface acoustic waves propagating on the piezoelectric substrate. Most of the piezoelectrically induced attenuation in the normal state is quenched when the film becomes superconducting. The residual attenuation that remains in the superconducting state may be related to the fact that the surface acoustic wave samples the sheet resistivity of a small number of granules.

• Research Organization: Wisconsin Univ., Milwaukee (USA). Dept. of Physics
• OSTI ID: 5999337
• Report Number(s): AD-A-148764/4/XAB
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATTENUATION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
ENERGY GAP
FILMS
LEAD
METALS
NIOBIUM COMPOUNDS
NIOBIUM NITRIDES
NITRIDES
NITROGEN COMPOUNDS
ORDER PARAMETERS
PHYSICAL PROPERTIES
PNICTIDES
REFRACTORY METAL COMPOUNDS
SUBSTRATES
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
WAVE PROPAGATION