Open AccessHard and soft x-rays XAS characterization of charge ordered LuFe2O4
Author(s) -
Sara Lafuerza,
J. Garcı́a,
G. Subı́as,
Javier Blasco,
Vera Cuartero,
Javier HerreroMartín
Publication year - 2015
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/592/1/012121
Subject(s) - x ray absorption spectroscopy , valence (chemistry) , materials science , absorption spectroscopy , anisotropy , crystallography , k edge , spectroscopy , characterization (materials science) , charge density , condensed matter physics , chemistry , nanotechnology , physics , optics , organic chemistry , quantum mechanics
International audienceThis work presents a thorough characterization of the mixed valence compound LuFe2O4 by means of x-ray absorption spectroscopy (XAS). Polarized XAS measurements at the Fe K-edge, Fe L-2,L-3-edges and O K-edge have been carried out to validate the bimodal Fe+2/Fe+3 charge ordering (CO) proposed to give rise to ferroelectricity at T-CO approximate to 320 K and also to study the anisotropy and temperature dependence of the Fe local structure. Our results discard a bimodal CO below TCO and agree with the presence of a Fe+2.5 +/-delta distribution with delta <= 0.25. Unexpectedly, the strong anisotropy of the hexagonal crystallographic structure is not reflected in either the Fe (4p, 3d) or the O (2p) density of unoccupied states. Finally, the so-called CO transition is originated by the ordering of local distortions as it is revealed by the temperature evolution of the XAS spectr