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Title: Distinguishing between the bi-stripe and Wigner-crystal model: A crystallographic study of charge-ordered La{sub 0.33}Ca{sub 0.67}MnO{sub 3}

Abstract

In order to resolve discrepancies in the charge-ordered structure between the Wigner-crystal and bi-stripe models, La{sub 0.33}Ca{sub 0.67}MnO{sub 3} was studied using quantitative electron diffraction and high-resolution imaging. Image simulations based on dynamic electron-diffraction theory suggest that the apparent difference in spacing between the Mn{sup 3+}-Mn{sup 3+} and Mn{sup 3+}-Mn{sup 4+} stripes, which is the basis of the bi-stripe model, can vary significantly with imaging conditions and may not directly represent the difference in actual spacing of atomic planes. Electron-diffraction study of crystal regions far away from defects, using parallel and convergent beams, reveal the existence of a[0 0 1] glide planes and n[1 0 0] diagonal glide planes that are incompatible with the large longitudinal displacement of the bi-stripe model. Although our study supports the Wigner-crystal model, detailed analysis suggests that, in our samples, the incommensurate charge modulation in the material has an average wave vector q=(0.284, 0, {xi}) with |{xi}|=0.010. The symmetry breaking associated with the small component {xi} along the c axis has not been previously observed by high-resolution x-ray or neutron powder diffraction. (c) 2000 The American Physical Society.

Authors:
 [1];  [2];  [1];  [1];  [1]
  1. Department of Applied Science, Brookhaven National Laboratory, Upton, New York 11973 (United States)
  2. (China)
Publication Date:
OSTI Identifier:
20216411
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 61; Journal Issue: 18; Other Information: PBD: 1 May 2000; Journal ID: ISSN 1098-0121
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CRYSTAL STRUCTURE; WIGNER THEORY; LANTHANUM OXIDES; CALCIUM OXIDES; MANGANESE OXIDES; X-RAY DIFFRACTION; ORDER-DISORDER TRANSFORMATIONS; NEUTRON DIFFRACTION; MANGANESE IONS; ELECTRON DIFFRACTION; CRYSTAL DEFECTS; EXPERIMENTAL DATA; THEORETICAL DATA

Citation Formats

Wang, Renhui, Department of Physics, Wuhan University, Wuhan 430 072,, Gui, Jianian, Zhu, Yimei, and Moodenbaugh, A. R. Distinguishing between the bi-stripe and Wigner-crystal model: A crystallographic study of charge-ordered La{sub 0.33}Ca{sub 0.67}MnO{sub 3}. United States: N. p., 2000. Web. doi:10.1103/PhysRevB.61.11946.
Wang, Renhui, Department of Physics, Wuhan University, Wuhan 430 072,, Gui, Jianian, Zhu, Yimei, & Moodenbaugh, A. R. Distinguishing between the bi-stripe and Wigner-crystal model: A crystallographic study of charge-ordered La{sub 0.33}Ca{sub 0.67}MnO{sub 3}. United States. doi:10.1103/PhysRevB.61.11946.
Wang, Renhui, Department of Physics, Wuhan University, Wuhan 430 072,, Gui, Jianian, Zhu, Yimei, and Moodenbaugh, A. R. Mon . "Distinguishing between the bi-stripe and Wigner-crystal model: A crystallographic study of charge-ordered La{sub 0.33}Ca{sub 0.67}MnO{sub 3}". United States. doi:10.1103/PhysRevB.61.11946.
@article{osti_20216411,
title = {Distinguishing between the bi-stripe and Wigner-crystal model: A crystallographic study of charge-ordered La{sub 0.33}Ca{sub 0.67}MnO{sub 3}},
author = {Wang, Renhui and Department of Physics, Wuhan University, Wuhan 430 072, and Gui, Jianian and Zhu, Yimei and Moodenbaugh, A. R.},
abstractNote = {In order to resolve discrepancies in the charge-ordered structure between the Wigner-crystal and bi-stripe models, La{sub 0.33}Ca{sub 0.67}MnO{sub 3} was studied using quantitative electron diffraction and high-resolution imaging. Image simulations based on dynamic electron-diffraction theory suggest that the apparent difference in spacing between the Mn{sup 3+}-Mn{sup 3+} and Mn{sup 3+}-Mn{sup 4+} stripes, which is the basis of the bi-stripe model, can vary significantly with imaging conditions and may not directly represent the difference in actual spacing of atomic planes. Electron-diffraction study of crystal regions far away from defects, using parallel and convergent beams, reveal the existence of a[0 0 1] glide planes and n[1 0 0] diagonal glide planes that are incompatible with the large longitudinal displacement of the bi-stripe model. Although our study supports the Wigner-crystal model, detailed analysis suggests that, in our samples, the incommensurate charge modulation in the material has an average wave vector q=(0.284, 0, {xi}) with |{xi}|=0.010. The symmetry breaking associated with the small component {xi} along the c axis has not been previously observed by high-resolution x-ray or neutron powder diffraction. (c) 2000 The American Physical Society.},
doi = {10.1103/PhysRevB.61.11946},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {1098-0121},
number = 18,
volume = 61,
place = {United States},
year = {2000},
month = {5}
}