We have studied the tunneling characteristics of Gd and Al substituted YBa2Cu3O7−δ single crystals with Tc = 90 Kand 80 K respectively. The high-Tc superconductos were etched 30 min in a 1% Br solution in methanol and the tunnel barriers were formed by exposing the crystals to the ambient atmosphere for about 30 min. Pb film counterelectrodes were thermally evaporated through a metallic mask. No relevant differences have been found in the differential resistance vs voltage of undoped 90 K and Gd junctions, so confirming that Gd is substituting for Y. A different behavior has been found in the Al doped junctions that show smeared structures of reduced amplitude.
TUNNELING SPECTROSCOPY INTO SUBSTITUTED Y-BA-CU-O SYSTEMS
CUCOLO, Anna Maria;DI LEO, Rosario;NIGRO, Angela;ROMANO, Paola;
1994
Abstract
We have studied the tunneling characteristics of Gd and Al substituted YBa2Cu3O7−δ single crystals with Tc = 90 Kand 80 K respectively. The high-Tc superconductos were etched 30 min in a 1% Br solution in methanol and the tunnel barriers were formed by exposing the crystals to the ambient atmosphere for about 30 min. Pb film counterelectrodes were thermally evaporated through a metallic mask. No relevant differences have been found in the differential resistance vs voltage of undoped 90 K and Gd junctions, so confirming that Gd is substituting for Y. A different behavior has been found in the Al doped junctions that show smeared structures of reduced amplitude.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
