Influence of structural disorder on magnetic order: An ab initio study of amorphous Fe, Co, and Ni.

Abstract

The magnetic order in amorphous Fe, Co, and Ni is studied ab initio within the framework of density-functional theory and the local-spin-density approximation using the linear-muffin-tin-orbital method in the atomic-sphere approximation. Noncollinear magnetic structures are treated in a fully self-consistent manner for rather small supercells containing 16 atoms. The results for iron show that noncollinear structures are energetically lower than collinear ones at a density of 8.4 g/${\mathrm{cm}}^{3}$ and energetically equivalent at a density of 7.9 g/${\mathrm{cm}}^{3}$. At a density of 7.4 g/${\mathrm{cm}}^{3}$ amorphous iron remains ferromagnetic. Cobalt and nickel remain ferromagnetic upon structural disordering at the densities of the corresponding dense packed crystalline structures.