Superconductivity of Freestanding Tungsten Nanofeatures Grown by Focused-Ion-Beam

Freestanding tungsten composite nanofeatures were grown by focused-ion-beam-induced deposition with 1 pA ion beam current. The temperature dependent electrical measurements show that the flying nanoscale tungsten is conducting with a room temperature resistivity of 550 mu Omega cm. It is also superconducting with a T-c above 5.1 K and can be repeatedly thermally cycled. Our results suggest that FIB direct-writing of three-dimensional tungsten composites might be a potential approach to fabricate vertical nanodevices and mask-free superconducting devices.