Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Single spin detection by magnetic resonance force microscopy


Magnetic resonance imaging (MRI) is well known as a powerful technique for visualizing subsurface structures with three-dimensional spatial resolution. Pushing the resolution below 1?µm remains a major challenge, however, owing to the sensitivity limitations of conventional inductive detection techniques. Currently, the smallest volume elements in an image must contain at least 1012 nuclear spins for MRI-based microscopy1, or 107 electron spins for electron spin resonance microscopy2. Magnetic resonance force microscopy (MRFM) was proposed as a means to improve detection sensitivity to the single-spin level, and thus enable three-dimensional imaging of macromolecules (for example, proteins) with atomic resolution3,4. MRFM has also been proposed as a qubit readout device for spin-based quantum computers5,6. Here we report the detection of an individual electron spin by MRFM. A spatial resolution of 25?nm in one dimension was obtained for an unpaired spin in silicon dioxide. The measured signal is consistent with a model in which the spin is aligned parallel or anti-parallel to the effective field, with a rotating-frame relaxation time of 760?ms. The long relaxation time suggests that the state of an individual spin can be monitored for extended periods of time, even while subjected to a complex set of manipulations that are part of the MRFM measurement protocol.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Configuration of the single-spin MRFM experiment.
Figure 2: Timing diagram for the iOSCAR spin manipulation protocol.
Figure 3: Plots showing the spin signal as the sample was scanned laterally in the x direction for two values of external field: a, Bext = 34?mT, and b, Bext = 30?mT.
Figure 4: By measuring the spin signal energy as a function of detection bandwidth, the power spectral density of the spin signal amplitude Δf1(t) can be determined.

Similar content being viewed by others


  1. Ciobanu, L., Seeber, D. A. & Pennington, C. H. 3D MR microscopy with resolution 3.7?µm by 3.3?µm by 3.3?µm. J. Magn. Reson. 158, 178–182 (2002)

    Article  ADS  CAS  Google Scholar 

  2. Blank, A., Dunnam, C. R., Borbat, P. P. & Freed, J. H. High resolution electron spin resonance microscopy. J. Magn. Reson. 165, 116–127 (2003)

    Article  ADS  CAS  Google Scholar 

  3. Sidles, J. A. Folded Stern-Gerlach experiment as a means for detecting nuclear magnetic resonance in individual nuclei. Phys. Rev. Lett. 68, 1124–1127 (1992)

    Article  ADS  CAS  Google Scholar 

  4. Sidles, J. A. et al. Magnetic resonance force microscopy. Rev. Mod. Phys. 67, 249–265 (1995)

    Article  ADS  CAS  Google Scholar 

  5. DiVincenzo, D. P. Two-bit gates are universal for quantum computation. Phys. Rev. A. 51, 1015–1022 (1995)

    Article  ADS  CAS  Google Scholar 

  6. Berman, G. P., Doolen, G. D., Hammel, P. C. & Tsifrinovich, V. I. Solid-state nuclear-spin quantum computer based on magnetic resonance force microscopy. Phys. Rev. B 61, 14694–14699 (2000)

    Article  ADS  CAS  Google Scholar 

  7. Stowe, T. D. et al. Attonewton force detection using ultrathin silicon cantilevers. Appl. Phys. Lett. 71, 288–290 (1997)

    Article  ADS  CAS  Google Scholar 

  8. Chui, B.W. et al. Mass-loaded cantilevers with suppressed higher-order modes for magnetic resonance force microscopy. Technical Digest 12th Int. Conf. on Solid-State Sensors and Actuators (Transducers'03) 1120–1123 (IEEE, Piscataway, 2003).

  9. Stipe, B. C. et al. Electron spin relaxation near a micron-size ferromagnet. Phys. Rev. Lett. 87, 277602 (2001)

    Article  CAS  Google Scholar 

  10. Mozyrsky, D., Martin, I., Pelekhov, D. & Hammel, P. C. Theory of spin relaxation in magnetic resonance force microscopy. Appl. Phys. Lett. 82, 1278–1280 (2003)

    Article  ADS  CAS  Google Scholar 

  11. Berman, G. P., Gorshkov, V. N., Rugar, D. & Tsifrinovich, V. I. Spin relaxation caused by thermal excitations of high-frequency modes of cantilever vibration. Phys. Rev. B 68, 094402 (2003)

    Article  ADS  Google Scholar 

  12. Hannay, J. D., Chantrell, R. W. & Rugar, D. Thermal field fluctuations in a magnetic tip—implications for magnetic resonance force microscopy. J. Appl. Phys. 87, 6827–6829 (2000)

    Article  ADS  CAS  Google Scholar 

  13. Mamin, H. J., Budakian, R., Chui, B. W. & Rugar, D. Detection and manipulation of statistical polarization in small spin ensembles. Phys. Rev. Lett. 91, 207604 (2003)

    Article  ADS  CAS  Google Scholar 

  14. Castle, J. G., Feldman, D. W., Klemens, P. G. & Weeks, R. A. Electron spin-lattice relaxation at defect sites: E′ centers in synthetic quartz at 3 kilo-Oersteds. Phys. Rev. 130, 577–588 (1963)

    Article  ADS  CAS  Google Scholar 

  15. Albrecht, T. R., Grütter, P., Horne, D. & Rugar, D. Frequency modulation detection using high-Q cantilevers for enhanced force microscope sensitivity. J. Appl. Phys. 69, 668–673 (1991)

    Article  ADS  Google Scholar 

  16. Slichter, C. P. Principles of Magnetic Resonance, 3rd edn, 20–24 (Springer, Berlin, 1990)

    Book  Google Scholar 

  17. Berman, G. P., Kamenev, D. I. & Tsifrinovich, V. I. Stationary cantilever vibrations in oscillating-cantilever-driven adiabatic reversals: Magnetic-resonance-force-microscopy technique. Phys. Rev. A. 66, 023405 (2002)

    Article  ADS  Google Scholar 

  18. Berman, G. P., Borgonovi, F., Goan, H.-S., Gurvitz, S. A. & Tsifrinovich, V. I. Single-spin measurement and decoherence in magnetic-resonance force microscopy. Phys. Rev. B 67, 094425 (2003)

    Article  ADS  Google Scholar 

  19. Brun, T. A. & Goan, H.-S. Realistic simulations of single-spin nondemolition measurement by magnetic resonance force microscopy. Phys. Rev. A. 68, 032301 (2003)

    Article  ADS  MathSciNet  Google Scholar 

  20. Davenport, W. B. & Root, W. L. An Introduction to the Theory of Random Signals and Noise 104 (McGraw-Hill, New York, 1958)

    MATH  Google Scholar 

  21. Ting, M., Hero, A.O., Rugar, D., Yip, C.-Y. & Fessler, J.A. Electron spin detection in the frequency domain under the interrupted oscillating cantilever-driven adiabatic reversal (iOSCAR) protocol. Preprint at (2003).

  22. Manassen, Y., Hamers, R. J., Demuth, J. E. & Castellano, A. J. Direct observation of the precession of individual paramagnetic spins on oxidized silicon surfaces. Phys. Rev. Lett. 62, 2531–2534 (1989)

    Article  ADS  CAS  Google Scholar 

  23. Durkan, C. & Welland, M. E. Electronic spin detection in molecules using scanning-tunneling-microscopy-assisted electron-spin resonance. Appl. Phys. Lett. 80, 458–460 (2002)

    Article  ADS  CAS  Google Scholar 

  24. Wrachtrup, J., von Borczyskowski, C., Bernard, J., Orritt, M. & Brown, R. Optical-detection of magnetic resonance in a single molecule. Nature 363, 244–245 (1993)

    Article  ADS  CAS  Google Scholar 

  25. Köhler, J. et al. Magnetic resonance of a single molecular spin. Nature 363, 242–244 (1993)

    Article  ADS  Google Scholar 

  26. Jelezko, F. et al. Single spin states in a defect center resolved by optical spectroscopy. Appl. Phys. Lett. 81, 2160–2162 (2002)

    Article  ADS  CAS  Google Scholar 

  27. Elzerman, J. M. et al. Single shot read-out of an individual electron spin in a quantum dot. Nature (in the press)

  28. Jiang, H.-W., Xiao, M., Martin, I. & Yablonovitch, E. Electrical detection of electron spin resonance of a single spin in the SiO2 of a Si field effect transistor. Nature (in the press)

  29. Rugar, D., Yannoni, C. S. & Sidles, J. A. Mechanical detection of magnetic resonance. Nature 360, 563–566 (1992)

    Article  ADS  Google Scholar 

Download references


We thank J. Sidles, A. Hero, M. Ting, G. Berman, I. Martin, C. S. Yannoni and T. Kenny for discussions, and D. Pearson, Y. Hishinuma, M. Sherwood and C. Rettner for technical assistance. This work was supported by the DARPA Three-Dimensional Atomic-Scale Imaging programme administered through the US Army Research Office.

Author information

Authors and Affiliations


Corresponding author

Correspondence to D. Rugar.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Video

This animated movie illustrates the cantilever-driven spin inversions that occur during the iOSCAR spin manipulation protocol (see Fig. 2 in the paper). The “Lock” and “Anti-lock” states correspond to the spin being either aligned or anti-aligned with respect to the effective field in the rotating frame, resulting in either positive or negative cantilever frequency shifts, respectively. Each time the microwave field is interrupted, the spin switches between the locked and anti-locked states and the phase of the spin inversions with respect to the cantilever motion is reversed. (MP4 933 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Rugar, D., Budakian, R., Mamin, H. et al. Single spin detection by magnetic resonance force microscopy. Nature 430, 329–332 (2004).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing