| Numéro |
J. Phys. Colloques
Volume 50, Numéro C8, Novembre 1989
36th International Field Emission Symposium
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|---|---|---|
| Page(s) | C8-477 - C8-480 | |
| DOI | https://doi.org/10.1051/jphyscol:1989881 | |
J. Phys. Colloques 50 (1989) C8-477-C8-480
DOI: 10.1051/jphyscol:1989881
OXYGEN CONCENTRATION OF Eu1 Ba2 Cu3 O7-x IN VACUUM : AN ATOM PROBE STUDY II
P.P. CAMUS1, H.B. ELSWIJK2 et A.J. MELMED31 National Institute of Standards and Technology, Surface Science Division, Gaithersburg, MD 20899, U.S.A.
2 c/o Philips Research Laboratories, P.O. Box 80000, NL - 5600 JA Eindhoven, The Netherlands.
3 Custom Probes Unlimited, P.O. Box 3938, Gaithersburg, MD 20878 USA
Abstract
Atom Probe mass analysis using a wide acceptance angle instrument was used to measure the oxygen content and metallic stoichiometry of the near-surface region of the superconducting ceramic oxide Eu1 Ba2 Cu3 O7-x (x≈0.1) after exposure at 85K and room temperature in vacuum. An oxygen depleted layer formed by H2 imaging must be removed before bulk concentrations are obtained. Room temperature holding in vacuum overnight (≈18h) then depletes the surface of oxygen to a depth of greater than 4 layers (1.2nm). However, after holding the specimen at 85K for up to 3h either with or without an applied field, no detectable loss of oxygen occurred. Therefore, for short time vacuum exposures at liquid nitrogen temperatures and below, no oxygen loss is expected, however, significant oxygen loss occurs for 18h vacuum exposures at room temperature.