INVESTIGADORES
ALDAO celso Manuel
artículos
Título:
Disruption, Segregation, and Passivation for Pd and Noble Metal Overlayers on YBa2Cu3O6.9
Autor/es:
T.J. WAGENER; Y. GAO; I.M. VITOMIROV; C.M. ALDAO; J.J. JOYCE; C. CAPASSO; J.H. WEAVER
Revista:
PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS
Editorial:
APS
Referencias:
Año: 1988 vol. 38 p. 232 - 239
ISSN:
0163-1829
Resumen:
We have investigated interfaces formed when Pd and the noble metals Cu, Ag, and Au are deposited
onto polycrystalline samples of YBa2Cu306.& fractured in an ultrahigh vacuum. Synchrotron-
radiation photoemission results show that Cu and Pd overlayers leach oxygen from the underlying
YBa2Cu30&.9 substrate, disrupt the superconductor, and destroy electronic states near the
Fermi level. Interface reactions become kinetically limited at room temperature after the deposition
of -4 A of Cu or Pd, significantly sooner than for the reactive metals Fe, Al, Ti, and In.
The presence of Ba near the surface after the deposition of more than 100 A of Cu and Pd
reAects substrate disruption and subsequent surface segregation. In contrast, overlayers of Ag
and Au do not disrupt the superconductor substrate, no segregation is observed, but the overlayers
are nonuniform and the quality of passivation is in question for coverages (100 A.