Field-driven vortex pinning and flux quantization effects in W-C complex superconducting arrays using 3D nanoprinting

We report on a densely packed W-C nanoarray fabricated via 3D nanoprinting using He+ focused ion beam induceddeposition (FIBID), and provide a detailed investigation of its superconducting properties. The nanoarray consists ofinterconnected rectangular nano-objects (95 nm x 35 nm), laterally coupled in both x and y-directions through internano-object regions exhibiting reduced thickness and lower tungsten content. The spatial variation in thickness andtungsten content creates a periodic pinning landscape, where superconductivity is locally weakened. Compositionalanalysis reveals aWatomic concentration of 36% in the core of the nano-objects and 16-20% in the upper/lower layersand interconnecting regions, correlating with the observed variation in superconducting properties across the structure.Magnetotransport measurements reveal multiple, well-defined resistance minima across a wide reduced temperaturerange (t = T/Tc = 0.5 to 0.92). In the absence of a fixed underlying lattice, these minima are associated with vortexpinning, showing matching conditions between the vortex lattice and the square nanoarray geometry. In addition tovortex pinning phenomena, periodic magnetoresistance oscillations (MRO) are also observed, which may be associatedwith magnetic flux quantization effects and interference of circulating supercurrents within the periodic structure. Thisinterplay between vortex dynamics and quantum interference could point to the emergence of a collective quantumregime. These findings highlight the potential of 3D-FIBID nanostructures as a tunable platform to study quantumtransport phenomena and engineer superconducting devices.