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Title: Surface control of epitaxial manganite films via oxygen pressure

Abstract

The trend to reduce device dimensions demands increasing attention to atomic-scale details of structure of thin films as well as to pathways to control it. We found that this is of special importance in the systems with multiple competing interactions. We have used in situ scanning tunneling microscopy to image surfaces of La 5/8Ca 3/8MnO 3 films grown by pulsed laser deposition. The atomically resolved imaging was combined with in situ angle-resolved X-ray photoelectron spectroscopy. We find a strong effect of the background oxygen pressure during deposition on structural and chemical features of the film surface. Deposition at 50 mTorr of O 2 leads to mixed-terminated film surfaces, with B-site (MnO 2) termination being structurally imperfect at the atomic scale. Moreover, a relatively small reduction of the oxygen pressure to 20 mTorr results in a dramatic change of the surface structure leading to a nearly perfectly ordered B-site terminated surface with only a small fraction of A-site (La,Ca)O termination. This is accompanied, however, by surface roughening at a mesoscopic length scale. The results suggest that oxygen has a strong link to the adatom mobility during growth. The effect of the oxygen pressure on dopant surface segregation is also pronounced: Camore » surface segregation is decreased with oxygen pressure reduction.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1190748
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
ACS Nano
Additional Journal Information:
Journal Volume: 9; Journal Issue: 4; Journal ID: ISSN 1936-0851
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; perovskite manganite; pulsed laser deposition; scanning tunneling microscopy; x-ray photoelectron spectroscopy; surface structure

Citation Formats

Tselev, Alexander, Vasudevan, Rama K., Gianfrancesco, Anthony G., Qiao, Liang, Ganesh, Panchapakesan, Meyer, Tricia L., Lee, Ho Nyung, Biegalski, Michael D., Baddorf, Arthur P., and Kalinin, Sergei. Surface control of epitaxial manganite films via oxygen pressure. United States: N. p., 2015. Web. doi:10.1021/acsnano.5b00743.
Tselev, Alexander, Vasudevan, Rama K., Gianfrancesco, Anthony G., Qiao, Liang, Ganesh, Panchapakesan, Meyer, Tricia L., Lee, Ho Nyung, Biegalski, Michael D., Baddorf, Arthur P., & Kalinin, Sergei. Surface control of epitaxial manganite films via oxygen pressure. United States. doi:10.1021/acsnano.5b00743.
Tselev, Alexander, Vasudevan, Rama K., Gianfrancesco, Anthony G., Qiao, Liang, Ganesh, Panchapakesan, Meyer, Tricia L., Lee, Ho Nyung, Biegalski, Michael D., Baddorf, Arthur P., and Kalinin, Sergei. Wed . "Surface control of epitaxial manganite films via oxygen pressure". United States. doi:10.1021/acsnano.5b00743. https://www.osti.gov/servlets/purl/1190748.
@article{osti_1190748,
title = {Surface control of epitaxial manganite films via oxygen pressure},
author = {Tselev, Alexander and Vasudevan, Rama K. and Gianfrancesco, Anthony G. and Qiao, Liang and Ganesh, Panchapakesan and Meyer, Tricia L. and Lee, Ho Nyung and Biegalski, Michael D. and Baddorf, Arthur P. and Kalinin, Sergei},
abstractNote = {The trend to reduce device dimensions demands increasing attention to atomic-scale details of structure of thin films as well as to pathways to control it. We found that this is of special importance in the systems with multiple competing interactions. We have used in situ scanning tunneling microscopy to image surfaces of La5/8Ca3/8MnO3 films grown by pulsed laser deposition. The atomically resolved imaging was combined with in situ angle-resolved X-ray photoelectron spectroscopy. We find a strong effect of the background oxygen pressure during deposition on structural and chemical features of the film surface. Deposition at 50 mTorr of O2 leads to mixed-terminated film surfaces, with B-site (MnO2) termination being structurally imperfect at the atomic scale. Moreover, a relatively small reduction of the oxygen pressure to 20 mTorr results in a dramatic change of the surface structure leading to a nearly perfectly ordered B-site terminated surface with only a small fraction of A-site (La,Ca)O termination. This is accompanied, however, by surface roughening at a mesoscopic length scale. The results suggest that oxygen has a strong link to the adatom mobility during growth. The effect of the oxygen pressure on dopant surface segregation is also pronounced: Ca surface segregation is decreased with oxygen pressure reduction.},
doi = {10.1021/acsnano.5b00743},
journal = {ACS Nano},
number = 4,
volume = 9,
place = {United States},
year = {Wed Mar 11 00:00:00 EDT 2015},
month = {Wed Mar 11 00:00:00 EDT 2015}
}

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Cited by: 14 works
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