Compositional variation of magnetic moment, magnetic anisotropy energy and coercivity in Fe(1−x)M x (M = Co/Ni) nanowires: an ab initio study

Abstract

Ab initio simulations are used to investigate the magnetic and electronic properties of freestanding Fe(1−x)M x (M = Co/Ni) nanowires. The stability of the nanowires increases with Co (Ni) addition, as seen from the increase in cohesive energy. With the addition of Co (Ni), the average magnetic moment shows a monotonic decrease, in contrast to the Slater–Pauling behavior observed in bulk Fe–Co/Ni alloys. The magnetic anisotropy energy of the nanowire is observed to change sign, from a parallel alignment of spins along the wire axis, to a perpendicular alignment with the increase of Co and Ni content. The magnetic anisotropy energy variation is seen to be correlated with the orbital moment anisotropy. The coercivity, as calculated using the Jacobs–Bean model is observed to decrease with Co (Ni) addition to the nanowire.