Prediction of the site occupations of the ThMn12-type intermetallics YFe12−xMox by combining thermodynamic model with ab-initio calculations

Site occupations of atoms on sublattices of ThMn12-type intermetallics YFe12−xMox with different composition and temperature are predicted by combining the thermodynamic sublattice model with ab-initio energetic calculations on end-members. The results show that the ordering tendencies of different types of elements are mostly unvaried with respect to temperature. The 2a sublattice is occupied by the Y atoms exclusively, and the 8f and 8j sublattices are both occupied by the Fe atoms with nearly 100%, while the 8i sublattice is shared by Mo and Fe atoms. The predicted site occupancy fractions agree well with the available experimental data. For the nonstoichiometric compound YFe12−xMox, the site occupation of the Mo atoms in the 8i sublattice increases with Mo content when x ≤ 4. It is near 100% when x = 4. When x > 4, the Mo atoms also tend to occupy the 8j sublattice. The approach employed in the present paper is expected to be generalized to other complicated structures, once their crystallographic information is available.