Fe-based alloys, ab initio calculations, magnetic exchange interaction, Curie temperature
Abstract
In this paper, within the framework of density functional theory for the disordered phase A2 of Fe-Me alloys (Me = Al, Ga, Ge) the magnetic exchange constants Jij are calculated and the Curie temperatures TC are estimated in dependence of the concentration of Me = Al, Ga, Ge (in the range of 0 ≤ x ≤ 14 at. %) and the crystal lattice parameter (in the range of 2,7 ≤ a ≤ 3,0 Å). The Jij distribution obtained in the paper demonstrates non-linear behavior. The highest ferromagnetic interaction in the first coordination sphere is ≈23 meV. In the third coordination sphere, antiferromagnetic exchange interaction is observed, which reaches a value of ≈ –2,5 meV. Magnetic transition temperatures calculated using the mean field approximation based on the experimental values and the a0 parameters calculated within the density functional theory show the presence of a concentration range of 4 ≤ x ≤ 8 at. % in which TC increases. The cross-section of the calculated Curie temperature distribution shows that for all studied Fe-Me alloys with the lattice parameter a0 = 2,94 Å, it is possible to construct a dependence TC(x) that is in quality agreement with the experimental one.
Author Biographies
Mikhail Aleksandrovich Zagrebin, Chelyabinsk State University, Chelyabinsk
Dr. Sc. (Physics and Mathematics), Associate Professor, Professor, Radiophysics and Electronics Department
Ivan Alekseevich Markovich, Chelyabinsk State University, Chelyabinsk
Post-graduate Student, Mathematical and Computer Modeling Department
Andrey Sergeevich Kuznetsov, Chelyabinsk State University, Chelyabinsk
Laboratory Assistant, Researcher, Condensed Matter Physics Department
Mariya Viktorovna Matyunina, Chelyabinsk State University, Chelyabinsk
Cand. Sc. (Physics and Mathematics), Associate Professor, Condensed Matter Physics Department
Anatoliy Vladimirovich Butakov, Chelyabinsk State University, Chelyabinsk
Cand. Sc. (Physics and Mathematics), Associate Professor, Radiophysics and Electronics Department
