Using first-principles density functional theory, we have predicted equilibrium structures and electronic and magnetic properties of one-dimensional ferromagnetic Fe∕Pt∕Fe multilayer barcode nanowires. By increasing the thickness of the Pt layer and consequently reducing the thickness of the Fe layer in the nanowire in the ferromagnetic configuration, we found that the average magnetic moment per iron atom, μav, increases monotonically with an ∼1∕N(Fe) dependence, where N(Fe) is the number of Fe layers. The monotonic increase in average magnetic moment is attributed to the change in magnetic moment at the Fe-Pt interface, and a simple model is proposed to explain this ∼1∕N(Fe) variation of μav in the barcode wires. Modulation of the ferromagnetism based on the number of ferromagnetic and nonmagnetic layer sequences in the nanowire suggests the possible application of these nanowires in nanometer scale magnetic barcodes. Furthermore, analysis of the Kohn-Sham energy bands in barcode nanowires suggests strong dependence of spin-polarized conductance on the nonmagnetic Pt spacer layer thickness, opening up the possibility for their application in magnetoelectronics or spintronics
