Sputtered MoRe SQUID-on-tip for high-field magnetic and thermal nanoimaging

Abstract

Scanning nanoscale superconducting quantum interference devices (SQUIDs) are gaining interest as highly sensitive microscopic magnetic and thermal characterization tools of quantum and topological states of matter and devices. Here we introduce a novel technique of collimated differential-pressure magnetron sputtering for versatile self aligned fabrication of SQUID on tip (SOT) nanodevices, which cannot be produced by conventional sputtering methods due to their diffusive, rather than the required directional point-source, deposition. The new technique provides access to a broad range of superconducting materials and alloys beyond the elemental superconductors employed in the existing thermal deposition methods, opening the route to greatly enhanced SOT characteristics and functionalities. Utilizing this method, we have developed MoRe SOT devices with sub-50 nm diameter, magnetic flux sensitivity of 1.2 $\mu {\Phi }_0/H{z}^{1/2}$ up to 3 T at 4.2 K, and thermal sensitivity better than 4 $\mu K/H{z}^{1/2}$ up to 5 T, about five times higher than any previous report, paving the way to nanoscale imaging of magnetic and spintronic phenomena and of dissipation mechanisms in previously inaccessible quantum states of matter.

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Cited by in corpus (10)

• Technical Review: Imaging weak magnetic field patterns on the nanometer-scale and its application to 2D materials
• Long-range nontopological edge currents in charge-neutral graphene
• Magnetic, thermal, and topographic imaging with a nanometer-scale SQUID-on-cantilever scanning probe
• Imaging the Ettingshausen effect and cryogenic thermoelectric cooling in a van der Waals semimetal
• Scanning SQUID-on-tip microscope in a top-loading cryogen-free dilution refrigerator
• A femto-Tesla DC SQUID design for quantum-ready readouts
• Fabrication of Nb and MoGe SQUID-on-tip probes by magnetron sputtering
• Advanced SQUID-on-lever scanning probe for high-sensitivity magnetic microscopy with sub-100-nm spatial resolution
• Pulsed magnetic field gradient on a tip for nanoscale imaging of spins
• Improving spatial resolution of scanning SQUID microscopy with an on-chip design