Surface segregation of Ba in polycrystalline YBa2Cu3O7 oxides: The effect of silver

A. G. Schrott; G. Singco; K. N. Tu

doi:10.1063/1.102081

Surface segregation of Ba in polycrystalline YBa₂Cu₃O₇ oxides: The effect of silver

A. G. Schrott
, G. Singco
, K. N. Tu

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

9 Citations (Scopus)

Abstract

We have investigated the effect of annealing polycrystalline YBa₂Cu₃O_7-δ samples in a He ambient and in vacuum, on the composition of their internal surfaces. X-ray photoelectron spectroscopy (XPS) data indicate a decrease in the amount of BaCO₃ but a higher proportion of Ba at the near-surface region upon low-temperature annealing in He or vacuum. The latter effect seems to derive from the presence of a surface barrier for oxygen outdiffusion, and can be prevented by diffusing Ag into the polycrystalline sample. Changes in the cutoff energies of the ultraviolet photoelectron spectra indicate that a submonolayer coverage of Ag is sufficient to produce a change in the work function of 0.3 eV, corresponding to the lowering of the surface barrier.

Original language	English
Pages (from-to)	2126-2128
Journal	Applied Physics Letters
Volume	55
Issue number	20
DOIs	https://doi.org/10.1063/1.102081
Publication status	Published - 13 Nov 1989
Externally published	Yes

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title = "Surface segregation of Ba in polycrystalline YBa2Cu3O7 oxides: The effect of silver",

abstract = "We have investigated the effect of annealing polycrystalline YBa2Cu3O7-δ samples in a He ambient and in vacuum, on the composition of their internal surfaces. X-ray photoelectron spectroscopy (XPS) data indicate a decrease in the amount of BaCO3 but a higher proportion of Ba at the near-surface region upon low-temperature annealing in He or vacuum. The latter effect seems to derive from the presence of a surface barrier for oxygen outdiffusion, and can be prevented by diffusing Ag into the polycrystalline sample. Changes in the cutoff energies of the ultraviolet photoelectron spectra indicate that a submonolayer coverage of Ag is sufficient to produce a change in the work function of 0.3 eV, corresponding to the lowering of the surface barrier.",

author = "Schrott, \{A. G.\} and G. Singco and Tu, \{K. N.\}",

note = "Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].",

year = "1989",

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doi = "10.1063/1.102081",

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volume = "55",

pages = "2126--2128",

journal = "Applied Physics Letters",

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publisher = "American Institute of Physics",

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TY - JOUR

T1 - Surface segregation of Ba in polycrystalline YBa2Cu3O7 oxides

T2 - The effect of silver

AU - Schrott, A. G.

AU - Singco, G.

AU - Tu, K. N.

N1 - Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].

PY - 1989/11/13

Y1 - 1989/11/13

N2 - We have investigated the effect of annealing polycrystalline YBa2Cu3O7-δ samples in a He ambient and in vacuum, on the composition of their internal surfaces. X-ray photoelectron spectroscopy (XPS) data indicate a decrease in the amount of BaCO3 but a higher proportion of Ba at the near-surface region upon low-temperature annealing in He or vacuum. The latter effect seems to derive from the presence of a surface barrier for oxygen outdiffusion, and can be prevented by diffusing Ag into the polycrystalline sample. Changes in the cutoff energies of the ultraviolet photoelectron spectra indicate that a submonolayer coverage of Ag is sufficient to produce a change in the work function of 0.3 eV, corresponding to the lowering of the surface barrier.

AB - We have investigated the effect of annealing polycrystalline YBa2Cu3O7-δ samples in a He ambient and in vacuum, on the composition of their internal surfaces. X-ray photoelectron spectroscopy (XPS) data indicate a decrease in the amount of BaCO3 but a higher proportion of Ba at the near-surface region upon low-temperature annealing in He or vacuum. The latter effect seems to derive from the presence of a surface barrier for oxygen outdiffusion, and can be prevented by diffusing Ag into the polycrystalline sample. Changes in the cutoff energies of the ultraviolet photoelectron spectra indicate that a submonolayer coverage of Ag is sufficient to produce a change in the work function of 0.3 eV, corresponding to the lowering of the surface barrier.

UR - https://www.scopus.com/pages/publications/0347875214

UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-0347875214&origin=recordpage

U2 - 10.1063/1.102081

DO - 10.1063/1.102081

M3 - RGC 21 - Publication in refereed journal

SN - 0003-6951

VL - 55

SP - 2126

EP - 2128

JO - Applied Physics Letters

JF - Applied Physics Letters

IS - 20

ER -