Magnetic, Thermal, and Topographic Imaging with a Nanometer-Scale SQUID-On-Lever Scanning Probe

• DOI: 10.1103/physrevapplied.17.034002
• Publication Date: 2022-03-01T16:53:09Z
• Authors: M. Wyss; K. Bagani; D. Jetter; E. Marchiori; A. Vervelaki; B. Gross; J. Ridderbos; S. Gliga; C. Schönenberger; M. Poggio
• Keywords: Lever; Nanometre; Scanning SQUID microscopy

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 two-dimensional van der Waals materials. Here, we demonstrate scanning probe that combines the thermal provided by on-tip SQUID tip-sample distance control topographic contrast of non-contact atomic force microscope (AFM). We pattern SQUID, including its weak-link Josephson junctions, via focused ion beam milling at apex cantilever coated Nb, yielding sensor effective diameter 365 nm, field 9.5 $\text{nT}/\sqrt{\text{Hz}}$ 620 $\text{nK}/\sqrt{\text{Hz}}$, operating fields up to 1.0 T. The resulting SQUID-on-lever robust AFM-like expands reach sensitive beyond what currently possible.