Low Temperature Physics: 30, 591 (2004); https://doi.org/10.1063/1.1789917 (8 pages)
Физика Низких Температур: Том 30, Выпуск 7-8 (Июль 2004), c. 785-794    ( к оглавлению , назад )

Advances in high-Tc grain boundary junctions

F. Tafuri

1INFM-Coherentia, Dip. Ingegneria dell'Informazione Seconda Universitб di Napoli, Aversa (CE), Italy
E-mail: tafuri@na.infn.it

J.R. Kirtley

IBM Watson Research Center, Route 134 Yorktown Heights, NY, USA

F. Lombardi

Department of Microelectronics and Nanoscience, MINA Chalmers University of Technology and Gцteborg University, S-41296 Gцteborg, Sweden

P.G. Medaglia, P. Orgiani, and G. Balestrino

INFM-Coherentia, Dip. Ingegneria Meccanica, Universitá di Roma Tor Vergata, Roma, Italy

Received February 9, 2004


We review results on two novel types of grain boundary Josephson junctions in the high critical temperature cuprate superconductors. The quality of YBa2Cu3O7-d biepitaxial grain boundary Josephson junctions have been improved using a new growth geometry to the point that «tunnel-like» characteristics are reproducibly obtained. The consequent low barrier transmission probabilities are apparently favourable to isolate intrinsic d-wave induced effects. We also focus on peculiar aspects of spontaneous currents in HTS Josephson junctions, which are unique and reflect the intimate relation between vortex matter and the Josephson effect. Bicrystal grain boundary Josephson junctions have also been fabricated using artificial superlattice films with as few as six superconducting copper–oxygen planes. Extrinsic and intrinsic d-wave effects in these junctions are discussed within the framework of novel designs for p-circuitry and qubits.

74.72.-h - Cuprate superconductors (high-Tc and insulating parent compounds)
74.50.+r - Tunneling phenomena; point contacts, weak links, Josephson effects (for SQUIDs, see 85.25.Dq; for Josephson devices, see 85.25.Cp; for Josephson junction arrays, see 74.81.Fa)