Scanning SQUID susceptometers with sub-micron spatial resolution
| Autor: | Mark B. Ketchen, Jonathan Gibbons, Kathryn A. Moler, Eric Spanton, Colin L. Jermain, Gerald W. Gibson, Daniel C. Ralph, Johanna C. Palmstrom, Connor M. Holland, Martin E. Huber, Y. K. K. Fung, Daniel Schiessl, Aaron J. Rosenberg, John R. Kirtley, Lisa Paulius |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
business.industry Condensed Matter - Superconductivity FOS: Physical sciences Flux 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Magnetic field law.invention Superconductivity (cond-mat.supr-con) SQUID Optics Modulation law 0103 physical sciences Microscopy Pickup Sensitivity (control systems) 010306 general physics 0210 nano-technology business Instrumentation Image resolution |
| Zdroj: | Review of Scientific Instruments. 87:093702 |
| ISSN: | 1089-7623 0034-6748 |
| Popis: | 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 $\approx 2\mu\Phi_0/Hz^{1/2}$. 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. Comment: 13 figures |
| Databáze: | OpenAIRE |
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