[Ifeffit] fitting simultaneously two different K-edges

[María Elena Montero Cabrera]

Dear friends, Sam Webb, Bruce Ravel or any other,

I have XAFS measurements, performed at SSRL at room temperature, of three
compounds. All compounds have multielemental character and I have K-edge
XAFS of two elements in each compound. It is desirable to make IFEFFIT
fitting of both edges simultaneously. In all cases random solution of
competing elements is assumed, but there are ferroelectricity,
superconductivity or magnetic behaviors that are desirable to be explained.
In each case, XAFS would confirm or reject the random character of the
solution. I am not such an expert for resolving by myself how to fit
together two edges using Artemis software. I'll present each case in the
following:

1. rutheno-cuprate (Ru1-xNbx)Sr2Eu1.4 Ce0.6Cu2O10+δ compounds series was
studied in both Ru and Nb K-edges. Changes in interatomic distances that
could be obtained by EXAFS would tell something about oxygen octahedra
around Ru and Nb.

2. g-Fe1-xCrxO3 maghemite for x=0.25, 0.5 and 0.75 was investigated by XAFS
in both Fe and Cr K-edges. Possible distortion of oxygen octahedra around
both Fe(III) and Cr(III) cations would tell something about not confirmed
ferroelectricity.

3. LaFeNiTiO3 has been confirmed to display magnetic behavior and was
studied by its Fe and Ti K-edges. Interatomic distances that could be
obtained by EXAFS are interesting for checking possible preferential
occupation of sites by Fe or Ti atoms.

Would any of you, please, suggest how to use Artemis or Sixpack for solving
these problems?
Sincerely yours

-- 
María Elena

Dra. María Elena Montero Cabrera
Departamento de Medio Ambiente y Energía
Centro de Investigación en Materiales Avanzados (CIMAV)
Miguel de Cervantes 120, Compl. Ind. Chihuahua
Chihuahua CP 31109, Chih. México
Tel (614) 4391123
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