Magnetic properties of Fe–Ni alloy atom bridges

We investigate the magnetic properties of atom bridges, made of Fe and Ni, between a scanning tunneling microscope tip and a solid surface, within the density functional theory. We consider an Fe 1− α Ni α atom bridge with a twisted ladder structure. Relative to a pure Fe bridge which is in a high-spin ferromagnetic state, we calculate the magnetic moment of the bridge as α increases. On the basis of the calculation results, we show that the Fe and Ni atoms in the bridge also stay in high-spin ferromagnetic states (the magnetic moment per atom is ∼3 μ B for Fe and ∼0.9 μ B for Ni) as α increases, and the mean magnetic moment per atom decreases linearly with increasing α .