Quantitative structural refinement of mn K edge XANES in LaMnO3 and CaMnO3 perovskites

Monesi, C and Meneghini, C and Bardelli, F and Benfatto, M and Mobilio, S and Manju, U and Sarma, DD (2006) Quantitative structural refinement of mn K edge XANES in LaMnO3 and CaMnO3 perovskites. In: Symposium on Synchrotron Radiation and Materials Science held at the 2005 Spring Meeting of the European-Materials-Research-Society, , May 31-JUN 03, 2005, Strasbourg, France, pp. 158-164.

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Abstract

The special magnetotransport properties of hole doped manganese perovskites originate from a complex interplay among structural, magnetic and electronic degree of freedom. In this picture the local atomic structure around Mn ions plays a special role and this is the reason why short range order techniques like X-ray absorption spectroscopy (XAS) have been deeply exploited for studying these compounds. The analysis of near edge region features (XANES) of XAS spectra can provide very fine details of the local structure around Mn, complementary to the EXAFS, so contributing to the full understanding of the peculiar physical properties of these materials. Nevertheless the XANES analysis is complicated by the large amount of structural and electronic details involved making difficult the quantitative interpretation.This work exploits the recently developed MXAN code to achieve a full structural refinement of the Mn K edge XANES of LaMnO3 and CaMnO3 compounds; they are the end compounds of the doped manganite series LaxCa1-xMnO3, in which the Mn ions are present only in one charge state as Mn3+ and Mn4+ respectively. The good agreement between the results derived from the analysis of near edge and extended region of the XAS spectra demonstrates that a quantitative picture of the local structure call be obtained from structural refinement of Mn K edge XANES data in these crystalline compounds. The XANES analysis offers, in addition.. the possibility to directly achieve information on the topology of local atomic structure around the absorber not directly achievable from EXAFS.

Item Type:	Conference Paper
Publication:	NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	XANES;colossal-magnetoresistance; structure.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	28 Sep 2010 11:14
Last Modified:	28 Sep 2010 11:14
URI:	http://eprints.iisc.ac.in/id/eprint/31624

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