Scanning SQUID microscopy in a cryogen-free dilution refrigerator
Abstract
We report a scanning superconducting quantum interference device (SQUID) microscope in a cryogen-free dilution refrigerator with a base temperature at the sample stage of at least 30 mK. The microscope is rigidly mounted to the mixing chamber plate to optimize thermal anchoring of the sample. The microscope housing fits into the bore of a superconducting vector magnet, and our design accommodates a large number of wires connecting the sample and sensor. Through a combination of vibration isolation in the cryostat and a rigid microscope housing, we achieve relative vibrations between the SQUID and the sample that allow us to image with micrometer resolution over a 150 µm range while the sample stage temperature remains at base temperature. To demonstrate the capabilities of our system, we show images acquired simultaneously of the static magnetic field, magnetic susceptibility, and magnetic fields produced by a current above a superconducting micrometer-scale device.
Citation
Low , D , Ferguson , G M , Jarjour , A , Schaefer , B T , Bachmann , M D , Moll , P J W & Nowack , K C 2021 , ' Scanning SQUID microscopy in a cryogen-free dilution refrigerator ' , Review of Scientific Instruments , vol. 92 , no. 8 , 083704 . https://doi.org/10.1063/5.0047652
Publication
Review of Scientific Instruments
Status
Peer reviewed
ISSN
0034-6748Type
Journal article
Rights
Copyright © 2021 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license.
Description
Funding: This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Award No. DE-SC0015947 (scanning SQUID imaging and implementation of millikelvin microscopes) and the Cornell Center of Materials Research with funding from the NSF MRSEC program under Award No. DMR-1719875 (SQUID and microscope design). Fabrication of the microstructures was supported by the Max Planck Society and by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) (Grant No. MO 3077/1-1) and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 715730).Collections
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