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Title: Local lattice effects in oxides

Abstract

Neutron diffraction measurements were used to investigate the local atomic structure of manganese and cobalt oxides. Static Jahn-Teller (JT) distortions present in the lightly doped perovskite manganates were found in metallic compositions as well. The cooperativeness of the distortions is however lost as the doping is increased. In the two-layer manganates, the existence of a local JT effect helps explain the similarities in the properties between cubic and layered systems. In the cobalt system, the coupling strength of the lattice to the e{sub g} states during the thermal activation from the ground, low-spin (LS) state to an excited, intermediate (IS) or high-spin (HS) states for Co in LaCoO{sub 3} changes as a function of temperature. The introduction of extra carriers by doping of La{sub 1-x}Sr{sub x}CoO{sub 3} stabilizes the IS JT states, populated at a rate proportional to the charge density. The JT distortions induced in this system are dynamic in nature if compared to the ones in the manganates. (c) 1999 American Institute of Physics.

Authors:
 [1];  [1]
  1. Los Alamos National Laboratory, Condensed Matter and Thermal Physics Group, MST 10, MS K764, Los Alamos, New Mexico 87545 (United States)
Publication Date:
OSTI Identifier:
20216675
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 483; Journal Issue: 1; Other Information: PBD: 1 Sep 1999; Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; HIGH-TC SUPERCONDUCTORS; LANTHANUM OXIDES; STRONTIUM OXIDES; COBALT OXIDES; LATTICE VIBRATIONS; JAHN-TELLER EFFECT; POLARONS; ELECTRON-PHONON COUPLING; NEUTRON DIFFRACTION; EXPERIMENTAL DATA

Citation Formats

Louca, Despina, and Kwei, George H. Local lattice effects in oxides. United States: N. p., 1999. Web. doi:10.1063/1.59604.
Louca, Despina, & Kwei, George H. Local lattice effects in oxides. United States. doi:10.1063/1.59604.
Louca, Despina, and Kwei, George H. Wed . "Local lattice effects in oxides". United States. doi:10.1063/1.59604.
@article{osti_20216675,
title = {Local lattice effects in oxides},
author = {Louca, Despina and Kwei, George H.},
abstractNote = {Neutron diffraction measurements were used to investigate the local atomic structure of manganese and cobalt oxides. Static Jahn-Teller (JT) distortions present in the lightly doped perovskite manganates were found in metallic compositions as well. The cooperativeness of the distortions is however lost as the doping is increased. In the two-layer manganates, the existence of a local JT effect helps explain the similarities in the properties between cubic and layered systems. In the cobalt system, the coupling strength of the lattice to the e{sub g} states during the thermal activation from the ground, low-spin (LS) state to an excited, intermediate (IS) or high-spin (HS) states for Co in LaCoO{sub 3} changes as a function of temperature. The introduction of extra carriers by doping of La{sub 1-x}Sr{sub x}CoO{sub 3} stabilizes the IS JT states, populated at a rate proportional to the charge density. The JT distortions induced in this system are dynamic in nature if compared to the ones in the manganates. (c) 1999 American Institute of Physics.},
doi = {10.1063/1.59604},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 483,
place = {United States},
year = {1999},
month = {9}
}