Magnetoelectrical Transport Improvements of Postgrowth Annealed Iron–Cobalt Nanocomposites: A Possible Route for Future Room-Temperature Spintronics

Focused-electron-beam-induced deposition (FEBID) constitutes a direct-writing maskless technique, which has been employed to prepare nanodots, nanolines, as well as laminar and even three-dimensional nanostructures with potential in many technological fields. Here, we report direct-writing of functional nanostructures with the HFeCo3(CO)12 bimetallic carbonyl precursor. The metal content as well as the magnetotransport properties of Fe–Co–C–O deposits were reproducibly tuned upon ex situ postgrowth annealing at 100, 200, and 300 °C in a high-vacuum system. The atomic composition obtained by energy-dispersive X-ray spectroscopy (EDX) analysis revealed that carbonyl groups release during annealing, although principally sole oxygen is released from the deposits, yielding an atomic ratio of Co:Fe:C:O = 52:17:22:9 with respect to the atomic composition of as-grown Co:Fe:C:O = 41:13:26:20. Interestingly, the amorphous carbon contained in the as-grown material turns into graphite nanocrystals with an average siz...