Electronic structure and magnetism of Fe{sub 3{minus}x}V{sub x}X (X=Si, Ga, and Al) alloys by the KKR-CPA method
- Department of Physics, Northeastern University, Boston, Massachusetts 02115 (United States)
- Interfaculty Reactor Institute, Delft University of Technology, Mekelweg 15, 2629 JB Delft (The Netherlands)
- Faculty of Physics and Nuclear Techniques, Academy of Mining and Metallurgy, al. Mickiewicza 30, 30-073 Krakow (Poland)
We present first-principles charge- and spin-self-consistent electronic structure computations on the Heusler-type disordered alloys Fe{sub 3{minus}x}V{sub x}X for three different metalloids X=(Si,thinspGa, and Al). In these calculations we use the methodology based on the Korringa-Kohn-Rostoker formalism and the coherent-potential approximation generalized to treat disorder in multicomponent complex alloys. Exchange correlation effects are incorporated within the local spin density approximation. Total energy calculations for Fe{sub 3{minus}x}V{sub x}Si show that V substitutes preferentially on the Fe(B) site, not on the Fe(A,C) site, in agreement with experiment. Furthermore, calculations have been carried out for Fe{sub 3{minus}x}V{sub x}X alloys (with x=0.25, 0.50, and 0.75), together with the end compounds Fe{sub 3}X and Fe{sub 2}VX, and the limiting cases of a single V impurity in Fe{sub 3}X and a single Fe(B) impurity in Fe{sub 2}VX. We delineate clearly how the electronic states and magnetic moments at various sites in Fe{sub 3{minus}x}V{sub x}X evolve as a function of the V content and the metalloid valence. Notably, the spectrum of Fe{sub 3{minus}x}V{sub x}X (X=Al and Ga) develops a pseudogap for the majority as well as minority spin states around the Fermi energy in the V-rich regime, which, together with local moments of Fe(B) impurities, may play a role in the anomalous behavior of the transport properties. The total magnetic moment in Fe{sub 3{minus}x}V{sub x}Si is found to decrease {ital nonlinearly}, and the Fe(B) moment to {ital increase} with increasing {ital x}; this is in contrast to expectations of the {open_quotes}local environment{close_quotes} model, which holds that the total moment should vary linearly while the Fe(B) moment should remain constant. The common-band model, which describes the formation of bonding and antibonding states with different weights on the different atoms, however, provides insight into the electronic structure of this class of compounds. {copyright} {ital 1999} {ital The American Physical Society}
- OSTI ID:
- 690743
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 60, Issue 19; Other Information: PBD: Nov 1999
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of substitutions and defects in half-Heusler FeVSb studied by electron transport measurements and KKR-CPA electronic structure calculations
Compton study of Ni{sub 75}Cu{sub 25} and Ni{sub 75}Co{sub 25} disordered alloys: Theory and experiment