A theoretical investigation of alpha-Fe2O3-Cr2O3 solid solutions.
A theoretical investigation of alpha-Fe2O3-Cr2O3 solid solutions.
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DOI：
10.1039/b815907f
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发表时间：
2009-02
期刊：
影响因子：
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通讯作者：
S. Benny;R. Grau‐Crespo;N. D. de Leeuw
中科院分区：
文献类型：
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作者：
S. Benny;R. Grau‐Crespo;N. D. de Leeuw
我们研究了α-Fe（2）O（3）-Cr（2）O（3）固溶体的热力学稳定性作为温度和成分的函数，使用统计力学与基于经典原子间势的原子模拟技术相结合，并添加了模型磁相互作用哈密顿量。我们的计算表明，隔离的Fe和Cr阳离子是边际有利的能量相比，任何其他阳离子分布，事实上，任何阳离子配置的混合系统的能量总是略高于合并的能量的等量的纯氧化物分别。然而，混合的正焓足够小，以允许高度无序的固溶体在约400 K或更高的温度下稳定。我们已经调查的程度的阳离子无序和混合氧化物的有效细胞参数作为温度和组合物的函数，我们讨论的磁相互作用和晶格振动的固溶体的稳定性的影响。
We have examined the thermodynamic stability of alpha-Fe(2)O(3)-Cr(2)O(3) 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 approximately 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.