Microwave surface impedance of proximity-coupled Nb/Al bilayer films

Journal Article · Tue Aug 01 04:00:00 EDT 1995 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.52.4477· OSTI ID:90507

Pambianchi, M S; Mao, S N; Anlage, S M ^[1]

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1. Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742-4111 (United States)

The surface resistance and magnetic penetration depth in proximity-coupled superconductor/normal-metal (Nb/Al) bilayers are examined to study the electrodynamics of layered structures with spatially inhomogeneous superconducting order parameter. The effective penetration depth {lambda}{sub eff}({ital T}) obeys {Delta}{lambda}{sub eff}({ital T}){similar_to}{ital T}{sup {ital n}}, where {ital n}{le}1, at low temperatures, distinctly different from the exponential behavior of Nb. An accompanying drop in the surface resistance {ital R}{sub {ital s}} occurs in the same temperature range. A model of the bilayer electrodynamics explicitly including the effects of proximity coupling is developed, and the behavior of both {lambda}{sub eff} and {ital R}{sub {ital s}} is consistently described. We find that a treatment of coherence effects in the proximity-coupled normal-metal layer is necessary to properly describe the behavior of {ital R}{sub {ital s}}({ital T}).

• OSTI ID: 90507
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 6 Vol. 52; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ALUMINIUM
ELECTRIC CONDUCTIVITY
LAYERS
NIOBIUM
ORDER PARAMETERS
PENETRATION DEPTH
PROXIMITY EFFECT
SUPERCONDUCTIVITY
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0273-0400 K