Gruner, Markus Ernst; Adeagbo, Waheed A.; Zayak, Alexey T.; Hucht, Alfred; Entel, Peter:

Lattice dynamics and structural stability of ordered Fe3Ni, Fe3Pd and Fe3Pt alloys using density functional theory

In: Physical Review B: Condensed matter and materials physics, Jg. 81 (2010) ; Nr. 6, S. 064109 (13pp)
ISSN: 1098-0121
Zeitschriftenaufsatz / Fach: Physik
We investigate the binding surface along the Bain path and phonon dispersion relations for the cubic phase of the ferromagnetic binary alloys Fe3X(X=Ni,Pd,Pt) for L12 and D022 ordered phases from first principles by means of density functional theory. The phonon dispersion relations exhibit a softening of the transverse acoustic mode at the M point in the L12 phase in accordance with experiments for ordered Fe3Pt. This instability can be associated with a rotational movement of the Fe atoms around the Ni-group element in the neighboring layers and is accompanied by an extensive reconstruction of the Fermi surface. In addition, we find an incomplete softening in [111] direction which is strongest for Fe3Ni. We conclude that besides the valence electron density also the specific Fe-content and the masses of the alloying partners should be considered as parameters for the design of Fe-based functional magnetic materials.