Local deformations and chemical bonding in Fe-X (X = Si, Al, Ga, Ge) soft magnetic alloys

Abstract

Dilute alloys based on ferromagnetic bcc iron modified by 3p (Al, Si) and 4p (Ga, Ge) elements are studied using the methods of the density-functional theory. It is shown that the local deformations and solution energies depend on the position of an alloying element in the periodic system. The nature of Fe-X chemical bonding varies from weak metallic in Fe-Ga to strong quasi-covalent in Fe-Si, which determines the values of local deformations in these alloys. The formation of pairs of impurity atoms in the position of the next-nearest neighbors leads to tetragonal lattice deformations, the value of which is highest for Si and Ge. The role of local deformations in the formation of unusual magnetic properties of Fe-X alloys is discussed. © 2013 Pleiades Publishing, Ltd.