Numerical simulation of the lattice properties of Fe1- xCo xSi - strongly correlated electron systems.

Within the framework of a thermodynamic model, the phonon anharmonicity associated with both acoustic and optical vibrations of the crystal lattice is investigated. On this basis we have performed self-consistent simulations of thermal and elastic properties of FeSi and CoSi compounds and their solid solutions Fe1- xCo xSi ( x = 0.1, 0.3, 0.5), which are promising spintronic materials. The non-lattice contributions to the heat capacity and coefficient of thermal expansion of the considered systems have been established. It is shown that the Invar effect observed in Fe0.7Co0.3Si and Fe0.5Co0.5Si is associated with anomalies of their electronic and magnetic subsystems. [ABSTRACT FROM AUTHOR]