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Title: Charge ordering and phase competition in the layered perovskite LaSr{sub 2}Mn{sub 2}O{sub 7}

Abstract

Charge-lattice fluctuations are observed in the layered perovskite manganite LaSr{sub 2}Mn{sub 2}O{sub 7} by Raman spectroscopy at temperatures as high as 340 K, and with decreasing temperature they become static, forming a charge-ordered (CO) phase below T{sub CO}=210 K. In the static regime, superlattice reflections are observed by neutron and x-ray diffraction with a propagation vector (1/4, -1/4, 0). Crystallographic analysis of the CO state demonstrates that the degree of charge and orbital ordering in this manganite is weaker than that in the three-dimensional perovskite manganites. Below T{sub N}=170 K, type-A antiferromagnetism (AF) develops and competes with the charge ordering, causing it to eventually melt below T{sup *}=100 K. High-resolution diffraction measurements suggest that the CO and AF states do not coincide within the same region of material, but rather coexist as separate phases. The transition to type-A antiferromagnetism at lower temperatures is characterized by the competition between these two phases. (c) 2000 The American Physical Society.

Authors:
 [1];  [1];  [2];  [2];  [3];  [4];  [5];  [2];  [5]
  1. Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
  2. Materials Research Laboratory, University of California, Santa Barbara, California 93106 (United States)
  3. Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States)
  4. MST-10, Los Alamos National Laboratory, Los Alamos, New Mexico 80434 (United States)
  5. Department of Chemistry, University of California, Santa Barbara, California 93106 (United States)
Publication Date:
OSTI Identifier:
20216777
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 61; Journal Issue: 22; Other Information: PBD: 1 Jun 2000; Journal ID: ISSN 1098-0121
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; PEROVSKITES; LANTHANUM OXIDES; STRONTIUM OXIDES; MANGANESE OXIDES; HIGH-TC SUPERCONDUCTORS; TEMPERATURE RANGE 0065-0273 K; TEMPERATURE RANGE 0273-0400 K; LAYERS; X-RAY DIFFRACTION; NEUTRON DIFFRACTION; CRYSTAL STRUCTURE; ANTIFERROMAGNETIC MATERIALS; RAMAN SPECTRA; PHASE TRANSFORMATIONS; ELECTRON-PHONON COUPLING; EXPERIMENTAL DATA

Citation Formats

Argyriou, D. N., Bordallo, H. N., Campbell, B. J., Cheetham, A. K., Cox, D. E., Gardner, J. S., Hanif, K., Santos, A. dos, and Strouse, G. F. Charge ordering and phase competition in the layered perovskite LaSr{sub 2}Mn{sub 2}O{sub 7}. United States: N. p., 2000. Web. doi:10.1103/PhysRevB.61.15269.
Argyriou, D. N., Bordallo, H. N., Campbell, B. J., Cheetham, A. K., Cox, D. E., Gardner, J. S., Hanif, K., Santos, A. dos, & Strouse, G. F. Charge ordering and phase competition in the layered perovskite LaSr{sub 2}Mn{sub 2}O{sub 7}. United States. doi:10.1103/PhysRevB.61.15269.
Argyriou, D. N., Bordallo, H. N., Campbell, B. J., Cheetham, A. K., Cox, D. E., Gardner, J. S., Hanif, K., Santos, A. dos, and Strouse, G. F. Thu . "Charge ordering and phase competition in the layered perovskite LaSr{sub 2}Mn{sub 2}O{sub 7}". United States. doi:10.1103/PhysRevB.61.15269.
@article{osti_20216777,
title = {Charge ordering and phase competition in the layered perovskite LaSr{sub 2}Mn{sub 2}O{sub 7}},
author = {Argyriou, D. N. and Bordallo, H. N. and Campbell, B. J. and Cheetham, A. K. and Cox, D. E. and Gardner, J. S. and Hanif, K. and Santos, A. dos and Strouse, G. F.},
abstractNote = {Charge-lattice fluctuations are observed in the layered perovskite manganite LaSr{sub 2}Mn{sub 2}O{sub 7} by Raman spectroscopy at temperatures as high as 340 K, and with decreasing temperature they become static, forming a charge-ordered (CO) phase below T{sub CO}=210 K. In the static regime, superlattice reflections are observed by neutron and x-ray diffraction with a propagation vector (1/4, -1/4, 0). Crystallographic analysis of the CO state demonstrates that the degree of charge and orbital ordering in this manganite is weaker than that in the three-dimensional perovskite manganites. Below T{sub N}=170 K, type-A antiferromagnetism (AF) develops and competes with the charge ordering, causing it to eventually melt below T{sup *}=100 K. High-resolution diffraction measurements suggest that the CO and AF states do not coincide within the same region of material, but rather coexist as separate phases. The transition to type-A antiferromagnetism at lower temperatures is characterized by the competition between these two phases. (c) 2000 The American Physical Society.},
doi = {10.1103/PhysRevB.61.15269},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {1098-0121},
number = 22,
volume = 61,
place = {United States},
year = {2000},
month = {6}
}