Engineering the magnetic properties of Ge 1 − x Mn x nanowires

Possible origins of room-temperature ferromagnetism in GeMn nanowires (NWs) are investigated. Arrays of Ge 1 − x Mn x NWs and Ge ∕ Ge 1 − x Mn x nanocables (NCs) ( x = 1 % - 5 % ) have been synthesized within the pores of anodized alumina oxide (AAO) membranes. The influence of annealing on the magnetic properties of Ge 1 − x Mn x NWs is studied. The room-temperature ferromagnetism is preserved after the postfabrication annealing in inert atmosphere ( T ann = 750 ° C ) demonstrating overall compatibility of Ge 1 − x Mn x NWs with conventional complementary metal-oxide semiconductor technology. The role of oxygen in high- T C ferromagnetic ordering is investigated in double-phased NCs with a Ge sheath. Despite a barrier to oxygen migration from the AAO membrane, samples still display room-temperature ferromagnetism, hence, ruling out any significant role of oxygen in the explanation of the high T C in the system. The magnetic properties of the one-dimensional Ge 1 − x Mn x nanostructures can be understood by considering interface related phenomena.