Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Antao, S. M. Articles by Parise, J. B. Search for Related Content GeoRef GeoRef Citation

Effects of high pressure and high temperature on cation ordering in magnesioferrite, MgFe₂O₄, using in situ synchrotron X-ray powder diffraction up to 1430 K and 6 GPa

¹ Mineral Physics Institute and Department of Geosciences, State University of New York, Stony Brook, New York 11794-2100, U.S.A.
² Department of Chemistry, University of the West Indies, Mona, Kingston 7, Jamaica
³ European Synchrotron Radiation Facility, BP 220, F 38043 Grenoble, France

Correspondence: ^* E-mail sytle.antao{at}stonybrook.edu

Disorder in stoichiometric magnesioferrite, MgFe₂O₄, was determined from in situ synchrotron powder X-ray diffraction data [ = 0.3738(4) Å] at 6, 5, and 3 GPa and temperatures up to 1430 K. The a unit-cell parameter increases linearly on heating at the three different pressures. Higher pressures cause a smaller cell volume, as expected. Cation order was analyzed in terms of the inversion parameter, x, {^iv[Mg_1–xFe_x]^vi[Mg_x/2Fe_1–x/2]₂O₄} and the order parameter Q = 1 – (3/2)x. As pressure increases, the inversion parameter increases in inverse MgFe₂O₄ spinel. O’Neill and Navrotsky (1983) and Landau models were used to describe the equilibrium non-convergent ordering process in MgFe₂O₄, and they both fit the data well.