| Resumo: | [EN] The usage of focused beams of ions (FIBs) to induce the deposition of different materials represents an incredibly powerful tool for the design and patterning of functional nanostructures. Specifically, by scanning a Ga+ or He+ FIB over the surface of a sample over which a gaseous precursor material has previously been delivered, decomposition reactions are induced on the precursor, which result in its partial deposition on the substrate, patterned following the path traced by the FIB. This technique is named focused ion beam induced deposition (FIBID). Ga+ FIBID of the W(CO)6 precursor results in the growth of a material containing W and C, which is superconducting below 4.5 K. In combination with the patterning flexibility of FIBID, it thus represents a fascinating scenario for the investigation of several phenomena related to superconductivity. Specifically, Ga+ FIBID W-C nanowires are shown to sustain non-local long-range vortex transport: by injecting a current at one end of a nanowire subjected to an externally applied magnetic field, a Lorentz force is exerted on present vortices, which in turn push their neighbors and eventually reach the other end of the nanowire, yielding finite resistances in areas depleted of current. In addition, gate-voltage modulation of the critical current of Ga+ FIBID nanowires, akin to a field-effect transistor geometry, is reported for this material for the first time. The speed of FIBID can be drastically increased when the procedure is performed below the condensation temperature of the precursor material, which aggregates forming a thick layer available for the FIB to decompose. This approach, named Cryo-FIBID, is shown to yield a W-containing material with metallic behavior. The deposition growth rate is found to increase by up to three orders of magnitude, and the resulting deposits can be used as auxiliary contacts for electrical measurements. Last, the patterning resolution of FIBID is significantly enhanced when using He+ ions. Deposition of in-plane nanostructures using the W(CO)6 precursor allows for patterning down to 10 nm in lateral size, with the deposits exhibiting type-II superconductivity below 2.5-4 K. The nanostructures are also found to sustain long-range non-local vortex motion.
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