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arXiv · 1903.11262

3D nano-bridge-based SQUID susceptometers for scanning magnetic imaging of quantum materials

Y. P. Pan·S. Y. Wang·X. Y. Liu·Y. S. Lin·L. X. Ma·Y. Feng·Z. Wang·L. Chen·Y. H. Wang
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Abstract

We designed and fabricated a new type of superconducting quantum interference device (SQUID) susceptometers for magnetic imaging of quantum materials. The 2-junction SQUID sensors employ 3D Nb nano-bridges fabricated using electron beam lithography. The two counter-wound balanced pickup loops of the SQUID enable gradiometric measurement and they are surrounded by a one-turn field coil for susceptibility measurements. The smallest pickup loop of the SQUIDs were 1 ${\mu}m$ in diameter and the flux noise was around 1 $\mu{\Phi}_0/\sqrt{Hz}$ at 100 Hz. We demonstrate scanning magnetometry, susceptometry and current magnetometry on some test samples using these nano-SQUIDs.

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Y. P. Pan, S. Y. Wang, X. Y. Liu, Y. S. Lin, L. X. Ma, Y. Feng, Z. Wang, L. Chen, Y. H. Wang. 2019-03-27. 3D nano-bridge-based SQUID susceptometers for scanning magnetic imaging of quantum materials. https://doi.org/10.1088/1361-6528%2Fab1792

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