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 DO22 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 Fe3 Ni. 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.
@article{arxiv.0911.3115,
title = {Lattice dynamics and structural stability of ordered Fe3Ni, Fe3Pd and Fe3Pt alloys},
author = {Markus E. Gruner and Waheed A. Adeagbo and Alexey T. Zayak and Alfred Hucht and Peter Entel},
journal= {arXiv preprint arXiv:0911.3115},
year = {2011}
}
Comments
Revised version, accepted for publication in Physical Review B