Magnetic structure of ordered FeAl and FeV

First-principles augmented-spherical-wave fixed-spin-moment solutions of the Kohn-Sham band equations are used to study the volume dependence of the total energy and the local moments in ordered FeAl and FeV. The solutions yield volume ranges with stable ferromagnetic and metastable type-I antiferromagnetic states for both FeAl and FeV, with energy differences less than ≃0.5 mRy over a wide range of volumes around equilibrium. For FeV, an unstable mixed antiferromagnetic state with equal and opposite iron and vanadium local moments is also found. Solutions corresponding to type-II antiferromagnetism were not found. Near equilibrium iron local moments are ≃0.5${\mathrm{\mu }}_{\mathit{B}}$ for the antiferromagnetic state, and ≃0.7${\mathrm{\mu }}_{\mathit{B}}$ for the ferromagnetic state for FeAl, and ≃0.7${\mathrm{\mu }}_{\mathit{B}}$ for both the ferromagnetic and antiferromagnetic states in FeV. The calculated lattice constant at equilibrium is within 1.8% of the experimental value for FeAl, and within 1.4% for FeV.