Nanostructuring superconducting vortex matter with focused ion beams

et al.Focused ion beams provide new opportunities to create small nanofabricated structures. Materials where this technique is successfully applied are different from those that are widely used in e-beam or photolithography processes. Arrays of holes have been fabricated in several layered superconductors, such as the transition metal dichalcogenides. A focused ion beam system can be also used to deposit superconducting material. A Ga beam is used to decompose a precusor W(CO)6 molecule, giving an amorphous mixture of W-C-Ga-O which is superconducting below liquid helium temperatures. The amorphous nature of the deposit gives isotropic superconducting features, and vortex pinning is determined by the surface topography (or film thickness). Here we present vortex lattice images in an amorphous thin film with a nanofabricated array of dots. We find vortex confinement within the dots and inhomogeneous vortex distributions with large magnetic field gradients (around a Tesla in 10-20 nm). We discuss scaling behavior of the vortex lattice after nanofabrication. © 2014 Elsevier B.V. All rights reserved.We specially acknowledge support from COST MP1201 program. This work was supported by the Spanish MINECO (FIS2011-23488 and ACI2009-0905 programs), from DST (Indo-Spain initiative) by the Comunidad de Madrid through program Nanobiomagnet and by the Aragon Regional Governement.Peer Reviewe