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arXiv · 2109.06774

Magnetic, thermal, and topographic imaging with a nanometer-scale SQUID-on-cantilever scanning probe

M. Wyss·K. Bagani·D. Jetter·E. Marchiori·A. Vervelaki·B. Gross·J. Ridderbos·S. Gliga·C. Schönenberger·M. Poggio
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Abstract

Scanning superconducting quantum interference device (SQUID) microscopy is a magnetic imaging technique combining high-field sensitivity with nanometer-scale spatial resolution. State-of-the-art SQUID-on-tip probes are now playing an important role in mapping correlation phenomena, such as superconductivity and magnetism, which have recently been observed in two-dimensional van der Waals materials. Here, we demonstrate a scanning probe that combines the magnetic and thermal imaging provided by an on-tip SQUID with the tip-sample distance control and topographic contrast of a non-contact atomic force microscope (AFM). We pattern the nanometer-scale SQUID, including its weak-link Josephson junctions, via focused ion beam milling at the apex of a cantilever coated with Nb, yielding a sensor with an effective diameter of 365 nm, field sensitivity of 9.5 $\text{nT}/\sqrt{\text{Hz}}$ and thermal sensitivity of 620 $\text{nK}/\sqrt{\text{Hz}}$, operating in magnetic fields up to 1.0 T. The resulting SQUID-on-lever is a robust AFM-like scanning probe that expands the reach of sensitive nanometer-scale magnetic and thermal imaging beyond what is currently possible.

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M. Wyss, K. Bagani, D. Jetter, E. Marchiori, A. Vervelaki, B. Gross, J. Ridderbos, S. Gliga, C. Schönenberger, M. Poggio. 2021-09-14. Magnetic, thermal, and topographic imaging with a nanometer-scale SQUID-on-cantilever scanning probe. https://doi.org/10.1103/physrevapplied.17.034002

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