Direct-write, focused ion beam-deposited, 7 K superconducting C–Ga–O nanowire

We have fabricated C–Ga–O nanowires by gallium focused ion beam-induced deposition from the carbon-based precursor phenanthrene. The electrical conductivity of the nanowires is weakly temperature dependent below 300 K and indicates a transition to a superconducting state below Tc=7 K. We have measured the temperature dependence of the upper critical field Hc2(T) and estimate a zero temperature critical field of 8.8 T. The Tc of this material is approximately 40% higher than that of any other direct write nanowire, such as those based on C–W–Ga, expanding the possibility of fabricating direct-write nanostructures that superconduct above liquid helium temperatures.