Dislocation-mediated flux creep in Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8+. delta
- Kamerlingh Onnes Laboratorium der Rijksuniversiteit Leiden, P. O. Box 9506, 2300 RA Leiden, The Netherlands (NL)
We have investigated the possible role of two-dimensional vortex-lattice defects in thermally assisted flux flow for the very anisotropic high-temperature superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (Bi-Sr-Ca-Cu-O). At low current densities, this mechanism, which we shall refer to as plastic flux creep, is expected to prevail over creep of elastically correlated flux bundles, or elastic creep. It is assumed that vortices are pinned by oxygen vacancies, for which the elementary interaction is obtained. Measurements of the ac susceptibility in an applied dc field, {ital B}{sub {ital c}1}{lt}{mu}{sub 0}{ital H}{lt}0.2{ital B}{sub {ital c}2}, carried out using a sufficiently low driving-field amplitude, were performed on a Bi-Sr-Ca-Cu-O single-crystalline sample. It is shown that under the above assumptions the experimental data may be consistently interpreted. The field dependence of the activation barrier is explained. Furthermore, the irreversibility line is reproduced, as well as the shape of the ac-susceptibility transition. Deviations from the plastic-flux-creep model can be qualitatively understood using a criterion describing the crossover to elastic flux creep.
- OSTI ID:
- 5692068
- Journal Information:
- Physical Review, B: Condensed Matter; (USA), Vol. 43:16; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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BISMUTH OXIDES
MAGNETIC FLUX
CALCIUM OXIDES
COPPER OXIDES
STRONTIUM OXIDES
HIGH-TC SUPERCONDUCTORS
MAGNETIC SUSCEPTIBILITY
TWO-DIMENSIONAL CALCULATIONS
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
MAGNETIC PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
STRONTIUM COMPOUNDS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties