WOHLLEBEN EFFECT IN SMALL GRAINS OF BI-BASED HIGH-TEMPERATURE SUPERCONDUCTORS - EVIDENCE FOR INTRINSIC NATURE OF SPONTANEOUS CURRENTS

Authors
KNAUF N FISCHER J RODEN B BOROWSKI R FREITAG B BUCHNER B MICKLITZ H FREIMUTH A KATAEV V KHOMSKII DI
Citation
N. Knauf et al., WOHLLEBEN EFFECT IN SMALL GRAINS OF BI-BASED HIGH-TEMPERATURE SUPERCONDUCTORS - EVIDENCE FOR INTRINSIC NATURE OF SPONTANEOUS CURRENTS, Europhysics letters, 35(7), 1996, pp. 541-546
Citations number
22
Categorie Soggetti
Physics
Journal title
Europhysics letters → ACNP
ISSN journal
02955075
Volume
35
Issue
7
Year of publication
1996
Pages
541 - 546
Database
ISI
SICI code
0295-5075(1996)35:7<541:WEISGO>2.0.ZU;2-6
Abstract
We report on the observation of the Wohlleben effect (WE) in powders o f Bi-based high-temperature superconductors consisting of isolated gra ins with sizes of order 1 mu m In these small grains the Josephson con tacts with negative critical current (pi-junctions) generally involved to explain the WE must be able to carry a current density of order j approximate to 10(5)-10(6) A/cm(2) even close to T-c. Such high sponta neous currents can be explained, if such contacts are not ordinary tun neling Josephson junctions but superconductor-normal-metal-superconduc tor junctions and if the superconducting order parameter has d-wave sy mmetry.