Non-equilibrium phase regime and magnetic properties of co-evaporated Fe-V thin-films

At equiatomic composition, FeV alloys form metastable phases such as the B2 phase or a short-range ordered phase in favor of the equilibrium σ phase. In this regime, structural, magnetic, and vibrational properties are strongly influenced by atomic disorder. For thermally co-evaporated Fe 1 − x V x thin-films, the non-equilibrium phase diagram is explored and the short-range ordered phase that forms at equiatomic compositions is compared to its base-centered cubic counterpart. The results indicate that within the short-range ordered thin-films, the structural disorder is accompanied by an increase in chemical order, i.e. Fe and V atoms are their respective preferential nearest neighbors. These observations are important for a better understanding of recrystallization in nonmagnetic, short-range ordered templates, in which crystallization can be selectively triggered. • Deviation from Vegard’s rule and antiparallel alignment of Fe and V magnetic moments • Non-equilibrium, short-range ordered phase at intermediate Fe-V alloy composition • Observation of chemical ordering via decreased isomer shift and phonon softening