摘要
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 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 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.
基金
We would like to acknowledge support by the National Key R&D Program of China(Grant No.2021YFA1400100)
National Natural Science Foundation of China(Grant Nos.11827805 and 12150003)
Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01).All of the authors are grateful for the experimental assistance of Y.P.Pan,Y.Feng,X.D.Zhou,and W.X.Tang.
