Andreev reflections and critical currents in high Tc superconductors

Review of the critical current densities and magnetic irreversibilities in high Tc superconductors

“…(I lc) and Sect. [190,191] [192,193]. Finally, as will be discussed in sections 14 and 15, it is probable that the V (I ) of thin films is to a large extent imposed by intrinsic pinning.…”

“…4) If the weak links are of SNS rather than SIS type, as it is probably the case for most sintered YBaCUO materials [73,192,193] percolation problems [302], dimensionality effects as well as spin-glass like effects and so on [304,305]. We We wish here to emphasize three popular techniques among others.…”

The flux-line lattice in superconductors

“…M. Fisher et al (1990) and Gilchrist (1990) explain critical current and magnetic hysteresis of granular YBCO as due to Josephson junctions with randomly distributed vortices and with a Bean-Livingston surface barrier, see also Kugel and Rakhmanov (1992). Nikolsky (1989) discusses the possibility that the intergrain junctions are non-tunneling but of metallic kind, at which Andreev reflection of the quasiparticles occurs. Dobrosavljević-Grujić and Radović (1993) and Prokić et al (1995) calculate critical currents of superconductor-normal metal-superconductor junctions; see Deutscher and DeGennes (1969) and Deutscher (1991) for reviews on the related proximity effect and recent experiments on the proximity effect in HTSC edge-junctions (Antognazza et al 1995) and Nb/insulator/Nb junctions (Camerlingo et al 1995).…”