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 induced deposition (FIBID), and we provide a detailed investigation of its superconducting properties. The nanoarray consists of interconnected rectangular nano-objects (95 × 35 nm2), laterally coupled in both x and y directions through inter-nano-object regions exhibiting reduced thickness and lower tungsten content. The spatial variation in thickness and tungsten content creates a periodic pinning landscape, where superconductivity is locally weakened. Compositional analysis reveals a W atomic concentration of 36% in the core of the nano-objects and 16%–20% in the upper/lower layers and 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 temperature range (t = T/Tc = 0.5–0.92). In the absence of a fixed underlying lattice, these minima are associated with vortex pinning, showing matching conditions between the vortex lattice and the square nanoarray geometry. In addition to vortex pinning phenomena, periodic magnetoresistance oscillations are also observed, which may be associated with magnetic flux quantization effects and interference of circulating supercurrents within the periodic structure. This interplay between vortex dynamics and quantum interference could point to the emergence of a collective quantum regime. These findings highlight the potential of 3D-FIBID nanostructures as a tunable platform to study quantum transport phenomena and engineer superconducting devices.