Spacer induced magnetism and its effect on interlayer exchange coupling in Fe/(Pd, Cu, Au, Ag) multilayered nanowires

摘要

We have investigated the one dimensional Fe/Pd, Fe/Cu, Fe/Ag, and Fe/Au multilayered nanowire systems by using first principles density functional theory. Our study reveals a gain in the binding energies of these heterostructures regardless of nature of the spacer. We have identified the electronic structure dependent enhancement of magnetic properties, and a switching behavior of the interlayer exchange coupling, with respect to the nature and dimension of the nonmagnetic spacer layer. We observe a down-spin (minority) d-charge depletion at the Fe site and a up-spin d-charge gain at Pd site in Fe/Pd nanowire which accounts for the enhanced magnetic moment of the Fe atoms and the ferromagnetic behavior of the Pd, in contrast to the paramagnetism appearing in their bulk state. We find the interlayer exchange coupling, Iex, in Fe/Pd nanowire to be very strong, and it shows a change of sign and a decrease in magnitude with increase in Pd spacer width. On the other hand, Iex shows an unusual increasing trend with increase in the Cu spacer layer thickness.