[Ifeffit] Linear Combination Fitting using ATHENA

Latta, Drew E. dlatta at anl.gov
Mon Aug 12 10:20:31 CDT 2013

I would say that the Mossbauer isn't always quite straight forward, especially if the OP is working with nanoparticles. You have to find the right temperature where superparamagnetism is gone but the Verwey transition hasn't occurred to reliably fit the resulting Mossbauer spectra. (I'll assume from ignorance that that Mg-ferrites have Verwey transitions.)

I would think the two best end-members for the XAS LC fits are possibly magnetite (fully stoichiometric: Fe2+/Fe3+ = 0.5) and either maghemite (gamma-Fe2O3) or the fully oxidized Mg-ferrite. Which Fe2O3 are you using Teck Kwang Choo? If you are using the alpha-form (hematite) then I would suspect you might not get very good fits as the structural difference between maghemite and hematite significantly influence their XANES spectra.

I've had good success finding Fe2+/Fe3+ ratios in partially oxidized magnetites by using magnetite and maghemite as end-members in LC fits. So I think you should have reasonable success for the Mg-ferrites using the right end-members.

Contact me in person below, if you are interested in magnetite/maghemite standard spectra.


Drew Latta
Drew E. Latta, Ph.D.
Postdoctoral Associate

Molecular Environmental Science Group
Biosciences Division
Argonne National Laboratory
Building 203, Room E-105
9700 South Cass Avenue
Argonne, IL  60439

Phone: 1-630-252-3985
dlatta at anl.gov<mailto:dlatta at anl.gov>

From: ifeffit-bounces at millenia.cars.aps.anl.gov [mailto:ifeffit-bounces at millenia.cars.aps.anl.gov] On Behalf Of Alexandre dos Santos Anastacio
Sent: Monday, August 12, 2013 9:01 AM
To: XAFS Analysis using Ifeffit
Subject: Re: [Ifeffit] Linear Combination Fitting using ATHENA


maybe that fingerprinting technique would be Mossbauer spectroscopy. The Fe(II)/Fe(III) ratio comes easily and also there are lots of papers about Mg-ferrite, an example:



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20130812/165a16dc/attachment.html>

More information about the Ifeffit mailing list