Atomic site sensitivity of the energy loss magnetic chiral dichroic spectra of complex oxides

Journal Article · Fri Apr 01 00:00:00 EDT 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3556769· OSTI ID:21560134

Calmels, L ^[1]; Rusz, J ^[2]

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1. CEMES-CNRS, Universite de Toulouse, BP 94347, F-31055 Toulouse Cedex 4 (France)
2. Department of Physics and Astronomy, Uppsala University, PO Box 516, SE-75120 (Sweden)

The quantitative analysis of magnetic oxide core level spectra can become complicated when the magnetic atoms are located at several nonequivalent atomic sites in the crystal. This is, for instance, the case for Fe atoms in magnetite, which are located in tetrahedral and octahedral atomic sites; in this case, the x-ray magnetic circular dichroic (XMCD) spectra recorded at the L{sub 2,3} edge of Fe contain contributions from the different nonequivalent atomic sites, which unfortunately cannot be separated. Energy loss magnetic chiral dichroic (EMCD) spectra are the transmission electron microscope analogies of the XMCD spectra. One of the important differences between these two techniques of magnetic analysis is that EMCD uses a fast electron beam instead of polarized light. The fast electrons behave like Bloch states in the sample, and the fine structure of the EMCD spectra is strongly influenced by channeling and dynamical diffraction effects. These effects can be adjusted by changing the experimental configuration. We use theoretical calculations, which include dynamical diffraction effects and in which electronic transitions are treated in the atomic multiplet formalism, to show that the relative weight of the Fe atoms in different nonequivalent atomic sites can be changed by a proper choice of the position of the detector and of the magnetite sample orientation and thickness. We conclude that EMCD spectra could be used to isolate the magnetic contribution of atoms in each of the nonequivalent atomic sites, which would not be possible with XMCD techniques.

• OSTI ID: 21560134
• Journal Information: Journal of Applied Physics, Vol. 109, Issue 7; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: DOI: 10.1063/1.3556769; (c) 2011 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ATOMS
CONFIGURATION
CRYSTALS
DIFFRACTION
ELECTRON BEAMS
ENERGY LOSSES
FINE STRUCTURE
IRON COMPOUNDS
MAGNETIC CIRCULAR DICHROISM
MAGNETITE
ORIENTATION
OXIDES
POLARIZATION
SENSITIVITY
SPECTRA
THICKNESS
TRANSMISSION ELECTRON MICROSCOPY
X RADIATION
BEAMS
CHALCOGENIDES
COHERENT SCATTERING
DICHROISM
DIMENSIONS
ELECTROMAGNETIC RADIATION
ELECTRON MICROSCOPY
IONIZING RADIATIONS
IRON ORES
LEPTON BEAMS
LOSSES
MICROSCOPY
MINERALS
ORES
OXIDE MINERALS
OXYGEN COMPOUNDS
PARTICLE BEAMS
RADIATIONS
SCATTERING
TRANSITION ELEMENT COMPOUNDS