We report the fabrication of self-organized arrays of Fe nanostripes with a period of 3.5 nm, by sequential deposition of Fe and Ag on Mo(110). The wires display a strong in-plane uniaxial anisotropy along their length, and are superparamagnetic above Tb=185±15K. The large value of nucleation volumes, inferred from the analysis of the thermal dependence of coercivity below TB, suggests the existence of interactions between the wires.