Magnetic properties of one-dimensional parallel arrays of Josephson junctions

Book · Sat Dec 31 04:00:00 EST 1994

OSTI ID:64683

Miller, Jr, J H; Gunaratne, G H; Zou, Z; Davis, M F; Rampersad, H R; Fan, N Q; Wolfe, J C ^[1]

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1. Univ. of Houston, TX (United States). Texas Center for Superconductivity

A superconducting quantum interference grating (SQUIG), consisting of many Josephson junctions in parallel, exhibits quantum interference analogous to the optical interference pattern produced by a diffraction grating, just as the dc SQUID is the magnetic analog of the double slit in optics. The field-dependent critical current of a SQUIG with sufficiently low inductance exhibits a series of sharp peaks, similar to the position-dependent intensity of a multiple-slit interference pattern. Such a device has the potential for improved sensitivity as a magnetic sensor because of its enhanced flux-to-voltage transfer coefficient. The behavior is quite different, however, when the inductance is large. In this limit, the field-dependent critical current becomes extremely hysteretic and exhibits self-organized phase coherence, in which a peak in the critical current (indicating coherence of the junction phases) is observed after each reversal of the field sweep. The authors have observed this phenomenon in large inductance arrays with up to ten YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) bi-crystal grain boundary junctions in parallel. They have modeled the behavior using a Frenkel-Kontorova model generalized to include global interactions due to mutual inductance. According to the model calculations, self-organized phase coherence occurs when the system relaxes from its critical state, causing the phases to simultaneously relax to minima in the periodic potential representing the Josephson coupling energy, and thus to become coherent modulo 2{pi}.

• OSTI ID: 64683
• Report Number(s): CONF-940142--; ISBN 0-8194-1455-7
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BARIUM OXIDES
COPPER OXIDES
EXPERIMENTAL DATA
JOSEPHSON JUNCTIONS
MAGNETIC PROPERTIES
MATHEMATICAL MODELS
SQUID DEVICES
USES
YTTRIUM OXIDES