Thermal stability of Cu and Fe nitrides and their applications for writing locally spin valves

Abstract

We have studied the thermal stability of the Cu and Fe nitrides. These results show that a nanometer-thick Cu nitride film decomposes at the Fe4N growth temperature. Considering this, we propose for their use in spintronics, the room temperature growth of a nonmagnetic (FeN)/semiconducting (Cu3N) epitaxial nitride bilayer that transforms into a ferromagnetic (Fe4N)/metallic (Cu) one by mild thermal annealing at 700 K. This process can be employed to locally decompose by laser (or ion) irradiation FeN/Cu3N/Fe4N) trilayers, giving rise to an array of lithographically defined Fe4N/Cu/Fe4N spin valves surrounded by metal/semiconductor spacers.