Novel hysteresis effects in Nb/AlO sub x /Al/AlO sub x /Nb tunnel junctions

Journal Article · Fri Feb 15 00:00:00 EST 1991 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.348723· OSTI ID:5731439

Blamire, M G; Kirk, E C.G.; Somekh, R E; Evetts, J E ^[1]

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1. Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom (GB)

Measurements on current-biased Nb/AlO{sub {ital x}}/Al/AlO{sub {ital x}}/Nb double tunnel junction devices with very thin central Al layers show a novel double hysteretic structure in the subgap region. Similar junction structures have previously exhibited very large nonequilibrium effects; the effects reported here appear close to and above the equilibrium critical temperature of Al. A model is presented in which the hysteresis is shown to arise from a transition from finite to zero voltage across one barrier on increasing current, due to the nucleation of an inhomogeneous state in the ultrathin central Al layer in which normal and superconducting states coexist. This reverse switching effect is shown to arise from the self-shunting effect of low-gap regions. Predictions of this model are shown to agree with the experimental data.

• OSTI ID: 5731439
• Journal Information: Journal of Applied Physics; (USA), Vol. 69:4; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
ALUMINIUM
TUNNEL EFFECT
ALUMINIUM OXIDES
NIOBIUM
CRITICAL CURRENT
ENERGY GAP
HYSTERESIS
OXIDATION
SPUTTERING
SUPERCONDUCTING FILMS
SUPERCONDUCTING JUNCTIONS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
CURRENTS
ELECTRIC CURRENTS
ELEMENTS
FILMS
JUNCTIONS
METALS
OXIDES
OXYGEN COMPOUNDS
TRANSITION ELEMENTS
426001* - Engineering- Superconducting Devices & Circuits- (1990-)
360104 - Metals & Alloys- Physical Properties
360204 - Ceramics
Cermets
& Refractories- Physical Properties