Superconducting quantum interference devices (SQUIDs) are exceptionally sensitive magnetometers, capable of detecting weak magnetic fields. Miniaturizing these devices and integrating them onto scanning probes enables high-resolution imaging at low temperatures. Here, we fabricate nanometer-scale niobium SQUIDs with inner-loop sizes down to $10\mathrm{nm}$ at the apex of individual planar silicon cantilevers via a combination of wafer-scale optical lithography and focused ion beam (FIB) milling. These robust SQUID-on-lever probes overcome many of the limitations of existing devices, achieving spatial resolution better than 100 nm, magnetic flux sensitivity of 0.3 $\mathrm{\mu }{\mathrm{\Phi }}_0$/$\sqrt{\mathrm{Hz}}$, and operation in magnetic fields up to about 0.5 T at 4.2 K. Nanopatterning via $\mathrm{Ne}$- or $\mathrm{He}$-FIB milling allows for the incorporation of a modulation line for coupling magnetic flux into the SQUID or a third Josephson junction, for shifting its phase. Such advanced functionality, combined with high spatial resolution, large magnetic field range, and the ease of use of a cantilever-based scanning probe, extends the applicability of scanning SQUID microscopy to a wide range of magnetic, normally conducting, superconducting, and quantum Hall systems. We demonstrate magnetic imaging of skyrmions at the surface of bulk ${\mathrm{Cu}}_2{\mathrm{OSe}\mathrm{O}}_3$. Analysis of the point spread function determined from imaging a single skyrmion yields a full width at half maximum of 71 nm. Moreover, we image modulated magnetization patterns with a period of 65 nm.

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• Magnetic texture
• Magnetometry
• Superconductivity
• Nanotechnology
• SQUID
• Focused ion beam
• Lithography
• Scanning probe microscopy