<i>Ab initio</i>-based mean-field theory of the site occupation in the Fe-Cr<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>σ</mml:mi></mml:mrow></mml:math>-phase

Abstract

An efficient first-principles-based mean-field theory is applied to study the site occupations in the Fe-Cr $\ensuremath{\sigma}$ phase. It is based on the expansion of the total energy of a random alloy close to the equiatomic composition in the paramagnetic state in terms of the effective on-site interactions and takes into account longitudinal spin fluctuations at high temperatures. The calculated site occupation is in very good agreement with the existing experimental data.