We have applied the break junction technique to highly epitaxial c-axis oriented YBaCuO thin films with T-c(rho =0)=91K deposited on (001) SrTiO3 or LaAlO3 substrates by a high oxygen pressure d.c. sputtering technique. The film thickness was about 1500 Angstrom and a photolithographic process was used to reduce to 100 mum the junction width across the fracture. By this procedure, tunable resistance break junctions with tunneling current favored dong the ab-planes have been realized. The junctions were formed at low temperatures with freshly fractured surfaces and an inert tunnel barrier was created by helium gas or liquid. A good stability was obtained with the normal-state resistance R-N changing about 15% in the temperature range between 4.2 K and 100 K. We have measured the temperature dependence of the conductance maxima that are related to superconducting energy gap at the Fermi level.
Temperature dependence of gap related structures in YBa2Cu3O7-delta break junctions
BOBBA, Fabrizio;CUCOLO, Anna Maria;
2000-01-01
Abstract
We have applied the break junction technique to highly epitaxial c-axis oriented YBaCuO thin films with T-c(rho =0)=91K deposited on (001) SrTiO3 or LaAlO3 substrates by a high oxygen pressure d.c. sputtering technique. The film thickness was about 1500 Angstrom and a photolithographic process was used to reduce to 100 mum the junction width across the fracture. By this procedure, tunable resistance break junctions with tunneling current favored dong the ab-planes have been realized. The junctions were formed at low temperatures with freshly fractured surfaces and an inert tunnel barrier was created by helium gas or liquid. A good stability was obtained with the normal-state resistance R-N changing about 15% in the temperature range between 4.2 K and 100 K. We have measured the temperature dependence of the conductance maxima that are related to superconducting energy gap at the Fermi level.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
