Abstract A nanofabricated superconducting quantum interference device (nano-SQUID) is a direct and sensitive flux probe used for magnetic imaging of quantum materials and mesoscopic devices.Due to the functionalities of superconductive integrated circuits, nano-SQUIDs fabricated on chips are particularly versatile, but their spatial resolution has been limited by their planar geometries.Here, we fig leaf apron use femtosecond laser 3-dimensional (3D) lithography to print a needle onto a nano-SQUID susceptometer to overcome the limits of the planar structure.
The nanoneedle coated with a superconducting shell focused the flux from both the field coil and the sample.We performed scanning imaging with usssa pro m softballs such a needle-on-SQUID (NoS) device on superconducting test patterns with topographic feedback.The NoS showed improved spatial resolution in both magnetometry and susceptometry relative to the planarized counterpart.
This work serves as a proof-of-principle for integration and inductive coupling between superconducting 3D nanostructures and on-chip Josephson nanodevices.