Letter | Published:

Quantitative nanoscale vortex imaging using a cryogenic quantum magnetometer

Nature Nanotechnology volume 11, pages 677681 (2016) | Download Citation

Abstract

Microscopic studies of superconductors and their vortices play a pivotal role in understanding the mechanisms underlying superconductivity1,2,3,4,5. Local measurements of penetration depths6 or magnetic stray fields7 enable access to fundamental aspects such as nanoscale variations in superfluid densities6 or the order parameter symmetry of superconductors8. However, experimental tools that offer quantitative, nanoscale magnetometry and operate over large ranges of temperature and magnetic fields are still lacking. Here, we demonstrate the first operation of a cryogenic scanning quantum sensor in the form of a single nitrogen–vacancy electronic spin in diamond9,10,11, which is capable of overcoming these existing limitations. To demonstrate the power of our approach, we perform quantitative, nanoscale magnetic imaging of Pearl vortices in the cuprate superconductor YBa2Cu3O7–δ. With a sensor-to-sample distance of 10 nm, we observe striking deviations from the prevalent monopole approximation12 in our vortex stray-field images, and find excellent quantitative agreement with Pearl's analytic model13. Our experiments provide a non-invasive and unambiguous determination of the system's local penetration depth and are readily extended to higher temperatures and magnetic fields. These results demonstrate the potential of quantitative quantum sensors in benchmarking microscopic models of complex electronic systems and open the door for further exploration of strongly correlated electron physics using scanning nitrogen–vacancy magnetometry.

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Acknowledgements

The authors thank V. Jacques, A. Högele and S.D. Huber for discussions and feedback on the manuscript. The authors acknowledge Attocube Systems for support and the joint development of the microscope system used here. The authors also acknowledge financial support from SNI (NCCR QSIT), SNF grants 143697 and 155845, and EU FP7 grant 611143 (DIADEMS).

Author information

Affiliations

  1. Department of Physics, University of Basel, Klingelbergstrasse 82, Basel CH-4056, Switzerland

    • L. Thiel
    • , D. Rohner
    • , M. Ganzhorn
    • , P. Appel
    • , E. Neu
    •  & P. Maletinsky
  2. Physikalisches Institut and Center for Quantum Science (CQ) in LISA+, Universität Tübingen, Auf der Morgenstelle 14, D-72076 Tübingen, Germany

    • B. Müller
    • , R. Kleiner
    •  & D. Koelle

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Contributions

L.T., D.R. and M.G. carried out the experiment and analysed the data. E.N., P.A. and M.G. fabricated scanning probe tips. B.M., R.K. and D.K. grew the YBCO samples and provided valuable input for the experiment. All authors commented on the manuscript. P.M. wrote the manuscript, conceived the experiment and supervised the project.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to P. Maletinsky.

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DOI

https://doi.org/10.1038/nnano.2016.63

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