Issue 5, 2009

A theoretical investigation of α-Fe2O3–Cr2O3 solid solutions

Abstract

We have examined the thermodynamic stability of α-Fe2O3–Cr2O3 solid solutions as a function of temperature and composition, using a combination of statistical mechanics with atomistic simulation techniques based on classical interatomic potentials, and the addition of a model magnetic interaction Hamiltonian. Our calculations show that the segregation of the Fe and Cr cations is marginally favourable in energy compared to any other cation distribution, and in fact the energy of any cation configuration of the mixed system is always slightly higher than the combined energies of equivalent amounts of the pure oxides separately. However, the positive enthalpy of mixing is small enough to allow the stabilisation of highly disordered solid solutions at temperatures of ∼400 K or higher. We have investigated the degree of cation disorder and the effective cell parameters of the mixed oxide as functions of temperature and composition, and we discuss the effect of magnetic interactions and lattice vibrations on the stability of the solid solution.

Graphical abstract: A theoretical investigation of α-Fe2O3–Cr2O3 solid solutions

Article information

Article type
Paper
Submitted
11 Sep 2008
Accepted
30 Oct 2008
First published
09 Dec 2008

Phys. Chem. Chem. Phys., 2009,11, 808-815

A theoretical investigation of α-Fe2O3–Cr2O3 solid solutions

S. Benny, R. Grau-Crespo and N. H. de Leeuw, Phys. Chem. Chem. Phys., 2009, 11, 808 DOI: 10.1039/B815907F

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