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Title: On-line characterization of YBCO coated conductors using Raman spectroscopy methods.

Abstract

The use of Raman spectroscopy for on-line monitoring of the production of superconducting YBa2Cu3O6+X (YBCO) thin films on long-length metal tapes coated with textured buffer layers is reported for the first time. A methodology is described for obtaining Raman spectra of YBCO on moving tape exiting a metal-organic-chemical-vapor-deposition (MOCVD) enclosure. After baseline correction, the spectra recorded in this way show the expected phonons of the specific YBCO crystal orientation required for high supercurrent transport, as well as phonons of non-superconducting second-phase impurities when present. It is also possible to distinguish YBCO films that are properly textured from films having domains of misoriented YBCO grains. An investigation of the need for focus control on moving tape indicated that focusing of the laser on the surface of the highly reflective YBCO films exiting the MOCVD enclosure tends to produce aberrant photon bursts that swamp the Raman spectrum. These photon bursts are very likely a consequence of optical speckle effects induced by a combination of surface roughness, crystallographic texture, and/or local strain within the small grain microstructure of the YBCO film. Maintaining a slightly out-of-focus condition provides the best signal-to-noise ratio in terms of the obtained Raman spectra. In addition to examining movingmore » tape at the post-MOCVD stage, Raman spectra of the film surface can also be recorded after the oxygen anneal performed to bring the YBCO to the optimum superconducting state. Consideration is given to data processing methods that could be adapted to the on-line Raman spectra to allow the tagging of out-of-specification tape segments and, at a more advanced level, feedback control to the MOCVD process.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
EE
OSTI Identifier:
914897
Report Number(s):
ANL/CMT/JA-58131
Journal ID: ISSN 0003-7028; APSPA4; TRN: US200817%%1
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Appl. Spectrosc.; Journal Volume: 61; Journal Issue: 4 ; Apr. 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; YTTRIUM OXIDES; BARIUM OXIDES; COPPER OXIDES; RAMAN SPECTRA; RAMAN SPECTROSCOPY; ON-LINE MEASUREMENT SYSTEMS

Citation Formats

Maroni, V. A., Reeves, J. L., Schwab, G., Chemical Engineering, and SuperPower, Inc. On-line characterization of YBCO coated conductors using Raman spectroscopy methods.. United States: N. p., 2007. Web. doi:10.1366/000370207780466208.
Maroni, V. A., Reeves, J. L., Schwab, G., Chemical Engineering, & SuperPower, Inc. On-line characterization of YBCO coated conductors using Raman spectroscopy methods.. United States. doi:10.1366/000370207780466208.
Maroni, V. A., Reeves, J. L., Schwab, G., Chemical Engineering, and SuperPower, Inc. Sun . "On-line characterization of YBCO coated conductors using Raman spectroscopy methods.". United States. doi:10.1366/000370207780466208.
@article{osti_914897,
title = {On-line characterization of YBCO coated conductors using Raman spectroscopy methods.},
author = {Maroni, V. A. and Reeves, J. L. and Schwab, G. and Chemical Engineering and SuperPower, Inc.},
abstractNote = {The use of Raman spectroscopy for on-line monitoring of the production of superconducting YBa2Cu3O6+X (YBCO) thin films on long-length metal tapes coated with textured buffer layers is reported for the first time. A methodology is described for obtaining Raman spectra of YBCO on moving tape exiting a metal-organic-chemical-vapor-deposition (MOCVD) enclosure. After baseline correction, the spectra recorded in this way show the expected phonons of the specific YBCO crystal orientation required for high supercurrent transport, as well as phonons of non-superconducting second-phase impurities when present. It is also possible to distinguish YBCO films that are properly textured from films having domains of misoriented YBCO grains. An investigation of the need for focus control on moving tape indicated that focusing of the laser on the surface of the highly reflective YBCO films exiting the MOCVD enclosure tends to produce aberrant photon bursts that swamp the Raman spectrum. These photon bursts are very likely a consequence of optical speckle effects induced by a combination of surface roughness, crystallographic texture, and/or local strain within the small grain microstructure of the YBCO film. Maintaining a slightly out-of-focus condition provides the best signal-to-noise ratio in terms of the obtained Raman spectra. In addition to examining moving tape at the post-MOCVD stage, Raman spectra of the film surface can also be recorded after the oxygen anneal performed to bring the YBCO to the optimum superconducting state. Consideration is given to data processing methods that could be adapted to the on-line Raman spectra to allow the tagging of out-of-specification tape segments and, at a more advanced level, feedback control to the MOCVD process.},
doi = {10.1366/000370207780466208},
journal = {Appl. Spectrosc.},
number = 4 ; Apr. 2007,
volume = 61,
place = {United States},
year = {Sun Apr 01 00:00:00 EDT 2007},
month = {Sun Apr 01 00:00:00 EDT 2007}
}