Open AccessValence selective DAFS measurements of Mn in La 1/3 Ca 2/3 MnO 3
Author(s) -
Ravel Bruce,
Grenier Stéphane,
Renevier Hubert,
Eom ChangBeom
Publication year - 2001
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049500017246
Subject(s) - superlattice , valence (chemistry) , ion , charge ordering , scattering , antiferromagnetism , manganese , spectral line , condensed matter physics , manganite , anomalous scattering , chemistry , stoichiometry , lattice (music) , crystallography , materials science , physics , ferromagnetism , charge (physics) , optics , organic chemistry , quantum mechanics , astronomy , acoustics
The manganese perovskite system La 1‐ x Ca x MnO 3 displays a complex phase diagram of structural, magnetic, and transport properties with varying Ca concentration. At x = 2/3 and at low temperature, the system is antiferromagnetic with Mn 4+ and Mn 3+ ions occupying special positions in a charge‐ordered supperlattice. The charge ordering transition at about 260 K is characterized by the appearance of satellite peaks around certain strong normal lattice reflections. The normal lattice reflections are due to scattering from planes containing Mn 4+ and Mn 3+ ions in nearly stoichiometric proportion, however the superlattice reflections are due to scattering from planes containing only Mn 4+ ions. By measuring Diffraction Anomalous Fine‐Structure spectra on a superlattice reflection and its associated normal lattice reflection, it is possible to isolate absorption‐like spectra for the two Mn sites. Due to the weak intensity of these superlattice reflections, we were unable to obtain high quality near‐edge spectra for the superlattice reflection measured. However, the data offer useful information about the local electronic structures of the two Mn ions.