A study of oxygen diffusion in and out of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thin films

Journal Article · Mon Jun 01 04:00:00 EDT 1998 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.367947· OSTI ID:634204

Michaelis, A; Irene, E A ^[1]; Auciello, O; Krauss, A R ^[2]

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1. Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290 (United States)
2. Argonne National Laboratory, Argonne, Illinois 60439-4831 (United States)

The c-axis oriented YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) films with superconducting transition temperatures up to 89 K were prepared by ion beam sputter deposition on single crystal (100) MgO and (100) SrTiO{sub 3} substrates. The variation of the oxygen concentration {delta} during annealing in vacuum and in oxygen was measured {ital in situ} and in real time by means of spectroscopic ellipsometry. The ellipsometric measurables {Delta} and {Psi} were quantitatively correlated with {delta} at a photon energy of 4.1 eV. Changes of the oxygen concentration below 1{percent} were resolved. Measurements for different film thicknesses in the range from 15 to 100 nm provided information to elucidate the mechanisms for oxygen out- and in-diffusion. The oxygen out-diffusion rate depends on the layer thickness confirming a bulk diffusion mechanism. The oxygen in-diffusion is relatively independent of layer thickness suggesting that a surface/grain boundary diffusion mechanism is dominant in this case. Additionally, the effect of H{sub 2}O on the oxygen diffusion was studied. It was found that H{sub 2}O enhances the oxygen out-diffusion while the in-diffusion remains unchanged or even decreases. The present study shows that ellipsometry provides a powerful tool for the {ital in situ}, noninvasive, on-line control of the oxygen content of thin YBCO films. {copyright} {ital 1998 American Institute of Physics.}

• OSTI ID: 634204
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 12 Vol. 83; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
BARIUM COMPOUNDS
BARIUM OXIDES
COPPER OXIDES
ELLIPSOMETRY
ENERGY BEAM DEPOSITION
HIGH-TC SUPERCONDUCTORS
OXYGEN
PROCESS CONTROL
SELF-DIFFUSION
STOICHIOMETRY
SUPERCONDUCTING FILMS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES