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A scanning superconducting quantum interference device with single electron spin sensitivity

Abstract

Superconducting quantum interference devices (SQUIDs) can be used to detect weak magnetic fields and have traditionally been the most sensitive magnetometers available. However, because of their relatively large effective size (on the order of 1 µm)1,2,3,4, the devices have so far been unable to achieve the level of sensitivity required to detect the field generated by the spin magnetic moment (μB) of a single electron5,6. Here we show that nanoscale SQUIDs with diameters as small as 46 nm can be fabricated on the apex of a sharp tip. The nano-SQUIDs have an extremely low flux noise of 50 nΦ0 Hz−1/2 and a spin sensitivity of down to 0.38 μB Hz−1/2, which is almost two orders of magnitude better than previous devices2,3,7,8. They can also operate over a wide range of magnetic fields, providing a sensitivity of 0.6 μB Hz−1/2 at 1 T. The unique geometry of our nano-SQUIDs makes them well suited to scanning probe microscopy, and we use the devices to image vortices in a type II superconductor, spaced 120 nm apart, and to record magnetic fields due to alternating currents down to 50 nT.

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Figure 1: SEM images of SOT devices.
Figure 2: Quantum interference patterns and IV characteristics of several SOT devices at 4.2 K.
Figure 3: Flux and spin noise spectra of the SOTs at 4.2 K.
Figure 4: Calculated magnetic flux in the SOT loops versus xy position of a single spin 10 nm below the SQUID plane.
Figure 5: Scanning SOT microscopy images of vortex matter and of magnetic field distribution generated by a.c. current in a Nb film at 4.2 K.

References

  1. Cleuziou, J-P., Wernsdorfer, W., Bouchiat, V., Ondarçuhu, T. & Monthioux, M. Carbon nanotube superconducting quantum interference device. Nature Nanotech. 1, 53–59 (2006).

    Article  CAS  Google Scholar 

  2. Koshnick, N. C. et al. A terraced scanning superconducting quantum interference device susceptometer with submicron pickup loops. Appl. Phys. Lett. 93, 243101 (2008).

    Article  Google Scholar 

  3. Nagel, J. et al. Superconducting quantum interference devices with submicron Nb/HfTi/Nb junctions for investigation of small magnetic particles. Appl. Phys. Lett. 99, 032506 (2011).

    Article  Google Scholar 

  4. Veauvy, C., Hasselbach, K. & Mailly, D. Scanning µ-superconduction quantum interference device force microscope. Rev. Sci. Instrum. 73, 3825–3830 (2002).

    Article  CAS  Google Scholar 

  5. Rugar, D., Budakian, R., Mamin, H. J. & Chui, B. W. Single spin detection by magnetic resonance force microscopy. Nature 430, 329–332 (2004).

    Article  CAS  Google Scholar 

  6. Degen, C. L. & Home, J. P. Scanning probes: cold-atom microscope shapes up. Nature Nanotech. 6, 399–400 (2011).

    Article  CAS  Google Scholar 

  7. Hao, L. et al. Measurement and noise performance of nano-superconducting-quantum-interference devices fabricated by focused ion beam. Appl. Phys. Lett. 92, 192507 (2008).

    Article  Google Scholar 

  8. Finkler, A. et al. Self-aligned nanoscale SQUID on a tip. Nano Lett. 10, 1046–1049 (2010).

    Article  CAS  Google Scholar 

  9. Clarke, J. & Braginski, A. I. (eds) The SQUID Handbook: Fundamentals and Technology of SQUIDs and SQUID Systems Vol. I (Wiley VCH, 2006).

    Book  Google Scholar 

  10. Kirtley, J. R. Fundamental studies of superconductors using scanning magnetic imaging. Rep. Prog. Phys. 73, 126501 (2010).

    Article  Google Scholar 

  11. Foley, C. P. & Hilgenkamp, H. Why nanoSQUIDs are important: an introduction to the focus issue. Supercond. Sci. Technol. 22, 064001 (2009).

    Article  Google Scholar 

  12. Troeman, A. G. P. et al. NanoSQUIDs based on niobium constrictions. Nano Lett. 7, 2152–2156 (2007).

    Article  CAS  Google Scholar 

  13. Lam, S. K. H., Clem, J. R. & Yang, W. A nanoscale SQUID operating at high magnetic fields. Nanotechnology 22, 455501 (2011).

    Article  Google Scholar 

  14. Mandal, S. et al. The diamond superconducting quantum interference device. ACS Nano 5, 7144–7148 (2011).

    Article  CAS  Google Scholar 

  15. Tesche, C. D. & Clarke, J. DC SQUID: noise and optimization. J. Low Temp. Phys. 29, 301–331 (1977).

    Article  Google Scholar 

  16. Likharev, K. K. Superconducting weak links. Rev. Mod. Phys. 51, 101–159 (1979).

    Article  Google Scholar 

  17. Van Harlingen, D. J., Koch, R. H. & Clarke, J. Superconducting quantum interference device with very low magnetic flux noise energy. Appl. Phys. Lett. 41, 197–199 (1982).

    Article  Google Scholar 

  18. Awschalom, D. D. et al. Low‐noise modular microsusceptometer using nearly quantum limited dc SQUIDs. Appl. Phys. Lett. 53, 2108–2110 (1988).

    Article  Google Scholar 

  19. Levenson-Falk, E. M., Vijay, R., Antler, N. & Siddiqi, I. A dispersive nanoSQUID magnetometer for ultra-low noise, high bandwidth flux detection. Supercond. Sci. Technol. 26, 055015 (2013).

    Article  CAS  Google Scholar 

  20. Ketchen, M. B. et al. Design, fabrication, and performance of integrated miniature SQUID suseptometers. IEEE Trans. Magn. 25, 1212–1215 (1989).

    Article  Google Scholar 

  21. Huber, M. E. et al. Gradiometric micro-SQUID susceptometer for scanning measurements of mesoscopic samples. Rev. Sci. Instrum. 79, 053704 (2008).

    Article  Google Scholar 

  22. Budker, D. & Romalis, M. Optical magnetometry. Nature Phys. 3, 227–234 (2007).

    Article  CAS  Google Scholar 

  23. Waldherr, G. et al. High-dynamic-range magnetometry with a single nuclear spin in diamond. Nature Nanotech. 7, 105–108 (2012).

    Article  CAS  Google Scholar 

  24. Nusran, N. M., Momeen, M. U. & Gurudev Dutt, M. V. High-dynamic-range magnetometry with a single electronic spin in diamond. Nature Nanotech. 7, 109–113 (2012).

    Article  CAS  Google Scholar 

  25. Maletinsky, P. et al. A robust scanning diamond sensor for nanoscale imaging with single nitrogen-vacancy centres. Nature Nanotech. 7, 320–324 (2012).

    Article  CAS  Google Scholar 

  26. Rondin, L. et al. Nanoscale magnetic field mapping with a single spin scanning probe magnetometer. Appl. Phys. Lett. 100, 153118 (2012).

    Article  Google Scholar 

  27. Finkler, A. et al. Scanning superconducting quantum interference device on a tip for magnetic imaging of nanoscale phenomena. Rev. Sci. Instrum. 83, 073702 (2012).

    Article  CAS  Google Scholar 

  28. Tilbrook, D. L. NanoSQUID sensitivity for isolated dipoles and small spin populations. Supercond. Sci. Technol. 22, 064003 (2009).

    Article  Google Scholar 

  29. Bending, S. J. Local magnetic probes of superconductors. Adv. Phys. 48, 449–535 (1999).

    Article  CAS  Google Scholar 

  30. Matsuda, T. et al. Oscillating rows of vortices in superconductors. Science 7, 2136–2138 (2001).

    Article  Google Scholar 

  31. Auslaender, O. M. et al. Mechanics of individual isolated vortices in a cuprate superconductor. Nature Phys. 5, 35–39 (2009).

    Article  CAS  Google Scholar 

  32. Schwarz, A., Liebmann, M., Pi, U. H. & Wiesendanger, R. Real space visualization of thermal fluctuations in a triangular flux-line lattice. New J. Phys. 12, 033022 (2010).

    Article  Google Scholar 

  33. Huber, M. et al. DC SQUID series array amplifiers with 120 MHz bandwidth. IEEE Trans. Appl. Supercond. 11, 4048–4053 (2001).

    Article  Google Scholar 

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Acknowledgements

This work was supported by the European Research Council (ERC advanced grant) and by the Minerva Foundation with funding from the Federal German Ministry for Education and Research. Y.A. acknowledges support by the Azrieli Foundation and by the Fonds Québécois de la Recherche sur la Nature et les Technologies. M.H. acknowledges support from the Weston Visiting Professorship programme. E.Z. acknowledges support from the US–Israel Binational Science Foundation (BSF).

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Contributions

D.V. and Y.A. fabricated and measured the SOT devices. Y.A., M.R., Y.M. and L.N. developed the Pb deposition set-up. Y.M., M.R. and D.V. designed and built the Nb evaporator. L.E. designed and constructed the scanning SOT microscope. L.E., D.H. and J.C. carried out the magnetic imaging. D.H. performed numerical analysis and parametric fitting. A.F. and Y.S. contributed to the development of the SOTs and the microscope. M.H. developed the SQUID array readout system. D.V. and E.Z. co-wrote the paper. All authors contributed to the manuscript.

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Correspondence to Denis Vasyukov or Eli Zeldov.

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The authors declare no competing financial interests.

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Vasyukov, D., Anahory, Y., Embon, L. et al. A scanning superconducting quantum interference device with single electron spin sensitivity. Nature Nanotech 8, 639–644 (2013). https://doi.org/10.1038/nnano.2013.169

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