Construction of a 4.2 K Scanning NanoSQUID-on-Tip Microscope Incorporating Topographic Feedback

Scanning probe techniques provide access to local information not obtainable from bulk measurements of thermodynamic properties or transport. Nanoscale SQUIDs fabricated on the ends of quartz pipettes have recently emerged as high sensitivity cryogenic magnetometers and thermometers capable of providing the spatial resolution necessary for investigating mesoscopic transport phenomena.
I will describe the construction of a scanning probe microscope based on a nanoscale Pb SQUID fabricated on the tip of a quartz pipette. The microscope is designed to operate over a temperature range of 4.2-7 K and in magnetic fields of up to several Tesla, covering the operational range of our Pb SQUIDs. My talk will cover technical design considerations including vibration isolation of the cryostat and the integration of quartz tuning forks for topographic feedback, which is essential for maximizing ultimate spatial resolution by allowing accurate placement of the SQUID sensor in proximity to the sample.