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Scanning SQUID susceptometers with sub-micron spatial resolution

Cornell Affiliated Author(s)


John Kirtley
Lisa Paulius
Aaron Rosenberg
Johanna Palmstrom
Connor Holland
Eric Spanton
Daniel Schiessl
Colin Jermain
Jonathan Gibbons
Y.-K.-K. Fung
Martin Huber
Daniel Ralph
Mark Ketchen
Gerald Gibson
Kathryn Moler


Superconducting QUantum Interference Device (SQUID) microscopy has excellent magnetic field sensitivity, but suffers from modest spatial resolution when compared with other scanning probes. This spatial resolution is determined by both the size of the field sensitive area and the spacing between this area and the sample surface. In this paper we describe scanning SQUID susceptometers that achieve sub-micron spatial resolution while retaining a white noise floor flux sensitivity of ≈2μΦ0/Hz1/2. This high spatial resolution is accomplished by deep sub-micron feature sizes, well shielded pickup loops fabricated using a planarized process, and a deep etch step that minimizes the spacing between the sample surface and the SQUID pickup loop. We describe the design, modeling, fabrication, and testing of these sensors. Although sub-micron spatial resolution has been achieved previously in scanning SQUID sensors, our sensors not only achieve high spatial resolution but also have integrated modulation coils for flux feedback, integrated field coils for susceptibility measurements, and batch processing. They are therefore a generally applicable tool for imaging sample magnetization, currents, and susceptibilities with higher spatial resolution than previous susceptometers. © 2016 Author(s).

Date Published


AIP Publishing








Group (Lab)

Dan C. Ralph Group

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