Influence of a magnetic field on the two-dimensional phase transition in thin-film superconductors

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

DOI:https://doi.org/10.1103/PhysRevB.36.3638· OSTI ID:6293427

Garland, J C; Lee, H J

This paper reports an experimental study of the influence of a magnetic field on the phase transition and low-temperature dynamical properties of two-dimensional superconducting films. Five samples of granular indium/indium oxide composite films were studied, with sheet resistances varying from 945 to 3150 ..cap omega../D'Alembertian, and thicknesses from 100 to 250 A. Measurements were made of the resistance R(T,H) and of the current-voltage characteristics in perpendicular magnetic fields of maximum value 30 G. The temperature range investigated ranged from 0.7T/sub c//sub 0/ to 1.5T/sub c//sub 0/, where T/sub c//sub 0/ is the Bardeen-Cooper-Schrieffer mean-field transition temperature. In the temperature regime above T/sub c/, the Kosterlitz-Thouless vortex unbinding temperature, the resistance was found to obey universal magnetic field scaling. Below T/sub c/, the magnetoresistance displayed an activated temperature dependence characteristic of vortex pinning. The pinning activation energy U(H,T) increased with a Ginzburg-Landau temperature dependence below T/sub c/ and displayed an unusual magnetic field dependence, varying inversely with magnetic field below 1 G, but becoming independent of field in stronger fields. As T/sub c/ was approached from below, all signs of vortex pinning disappeared, with U(H,T/sub c/) = 0 and the magnetoresistance exhibiting linear Bardeen-Stephen behavior. These results are interpreted in the context of other work on two-dimensional superconductors.

• Research Organization: Department of Physics Ohio State University, Columbus, Ohio 43210
• OSTI ID: 6293427
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 36:7; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHALCOGENIDES
COMPOSITE MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
FILMS
GRANULAR MATERIALS
INDIUM
INDIUM COMPOUNDS
INDIUM OXIDES
MAGNETIC FLUX
MAGNETORESISTANCE
MATERIALS
METALS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SUPERCONDUCTING COMPOSITES
SUPERCONDUCTING FILMS
TEMPERATURE DEPENDENCE
ULTRALOW TEMPERATURE