Josephson coupling between superconducting clusters in crystals
Instituto de Física “Gleb Wataghin”, UNICAMP - 13083-970, Campinas,
Accepted: 19 May 2000
Diamagnetic moments for two Bi2Sr2CaCu2O crystals were measured at different fields H and temperatures. For the higher fields two distinct transition temperatures and are seen, with . By increasing H the line shifts very slowly while shifts much faster to lower temperatures, displaying a clear upward curvature well described by a theory based on Josephson coupling between superconducting clusters. We show further that is dependent on sample homogeneity, which is correlated with oxygen distribution in the high- superconductors.
PACS: 74.20.-z – Theories and models of superconducting state / 74.25.Ha – Magnetic properties / 74.50.+r – Proximity effects, weak links, tunneling phenomena, and Josephson effects
© EDP Sciences, 2000