Title

Interactions at the Superconductor-Metal Interface

Document Type

Article

Publication Date

1995

Abstract

The interfacial chemistry between a superconducting oxide (Y1Ba2Cu3O7−x) and metallic adsorbates has been studied with the idea of understanding what processing steps can modify the interface. X-ray Photoelectron Spectroscopy has been used to study the growth of Ag on this oxide during the initial stages of bond formation. These results have been compared to that of a more reactive metal such as Ni. It is seen that even though Ag grows as metallic atom and Ni grows as Ni-O at the first interfacial monolayer, the surface reduction of Cu is identical in the two cases. This indicates that in the absence of a thermodynamic redox reaction, there is no direct correlation between the oxygen affinity of the adsorbate and the extent of chemical reduction seen in surface copper ions. This apparent reduction, which may therefore arise from adatom-induced restructuring, can be prevented if the superconductor is exposed to bromine gas prior to silver deposition. These results have been analyzed in light of the available literature in this area. The possible impact of this finding on Ag-superconductor composite processing has been discussed.

DOI

dx.doi.org/10.1016/0964-1807(95)00025-Z