Skip to main content

Thank you for visiting nature.com. 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.

  • Article
  • Published:

Highly sensitive nanoscale spin-torque diode

Abstract

Highly sensitive microwave devices that are operational at room temperature are important for high-speed multiplex telecommunications. Quantum devices such as superconducting bolometers possess high performance but work only at low temperature. On the other hand, semiconductor devices, although enabling high-speed operation at room temperature, have poor signal-to-noise ratios. In this regard, the demonstration of a diode based on spin-torque-induced ferromagnetic resonance between nanomagnets represented a promising development, even though the rectification output was too small for applications (1.4 mV mW−1). Here we show that by applying d.c. bias currents to nanomagnets while precisely controlling their magnetization-potential profiles, a much greater radiofrequency detection sensitivity of 12,000 mV mW−1 is achievable at room temperature, exceeding that of semiconductor diode detectors (3,800 mV mW−1). Theoretical analysis reveals essential roles for nonlinear ferromagnetic resonance, which enhances the signal-to-noise ratio even at room temperature as the size of the magnets decreases.

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

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

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

Figure 1: Nonlinear effect in nanomagnets and the spin-torque diode device.
Figure 2: Basic device characteristics.
Figure 3: d.c. bias and RF input power dependence.
Figure 4: Noise characteristics.

Similar content being viewed by others

References

  1. Baibich, M. N. et al. Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices. Phys. Rev. Lett. 61, 2472–2475 (1988).

    Article  CAS  Google Scholar 

  2. Miyazaki, T. & Tezuka, N. Giant magnetic tunneling effect in Fe/Al2O3/Fe junction. J. Magn. Magn. Mater. 139, L231–L234 (1995).

    Article  CAS  Google Scholar 

  3. Moodera, J. S., Kinder, L. R., Wong, T. M. & Meservey, R. Large magnetoresistance at room temperature in ferromagnetic thin film tunnel junctions. Phys. Rev. Lett. 74, 3273–3276 (1995).

    Article  CAS  Google Scholar 

  4. Yuasa, S., Fukushima, A., Nagahama, T., Ando, K. & Suzuki, Y. High tunnel magnetoresistance at room temperature in fully epitaxial Fe/MgO/Fe tunnel junctions due to coherent spin-polarized tunneling. Jpn. J. Appl. Phys. 43, L588–L590 (2004).

    Article  CAS  Google Scholar 

  5. Parkin, S. S. P. et al. Giant tunneling magnetoresistance at room temperature with MgO (100) tunnel barriers. Nature Mater. 3, 862–867 (2004).

    Article  CAS  Google Scholar 

  6. Yuasa, S., Nagahama, T., Fukushima, A, Suzuki, Y. & Ando, K. Giant room-temperature magnetoresistance in single-crystal Fe/MgO/Fe magnetic tunnel junctions. Nature Mater. 3, 868–871 (2004).

    Article  CAS  Google Scholar 

  7. Djayaprawira, D. D. et al. 230% room-temperature magnetoresistance in CoFeB/MgO/CoFeB magnetic tunnel junctions. Appl. Phys. Lett. 86, 092502 (2005).

    Article  Google Scholar 

  8. Slonczewski, J. C. Current-driven excitation of magnetic multilayers. J. Magn. Magn. Mater. 159, L1–L7 (1996).

    Article  CAS  Google Scholar 

  9. Berger, L. Emission of spin waves by a magnetic multilayer traversed by a current. Phys. Rev. B 54, 9353–9358 (1996).

    Article  CAS  Google Scholar 

  10. Myers, E. B., Ralph, D. C., Katine, J. A., Louie, R. A. & Buhrman, R. A. Current-induced switching of domains in magnetic multilayer devices. Science 285, 867–870 (1999).

    Article  CAS  Google Scholar 

  11. Huai, Y., Albert, F., Nguyen, P., Pakala, M. & Valet, T. Observation of spin-transfer switching in deep submicron-sized and low resistance magnetic tunnel junctions. Appl. Phys. Lett. 84, 3118–3120 (2004).

    Article  CAS  Google Scholar 

  12. Kubota, H. et al. Evaluation of spin-transfer switching in CoFeB/MgO/CoFeB magnetic tunnel junctions. Jpn. J. Appl. Phys. 44, L1237–L1240 (2005).

    Article  CAS  Google Scholar 

  13. Diao, Z. et al. Spin transfer switching and spin polarization in magnetic tunnel junctions with MgO and AlOx barriers. Appl. Phys. Lett. 87, 232502 (2005).

    Article  Google Scholar 

  14. Tsoi, M. et al. Excitation of a magnetic multilayer by an electric current. Phys. Rev. Lett. 80, 4281–4284 (1998).

    Article  CAS  Google Scholar 

  15. Kiselev, S. et al. Microwave oscillations of a nanomagnet driven by a spin-polarized current. Nature 425, 380–382 (2003).

    Article  CAS  Google Scholar 

  16. Deac, A. et al. Bias-driven high-power microwave emission from MgO-based tunnel magnetoresistance devices. Nature Phys. 4, 803–809 (2008).

    Article  CAS  Google Scholar 

  17. Žutić, I., Fbrian, J. & Sarma, S.D. Spin-polarized transport in inhomogeneous magnetic semiconductors: Theory of magnetic/nonmagnetic p–n junctions. Phys. Rev. Lett. 88, 066603 (2002).

    Article  Google Scholar 

  18. Kondo, T., Hayafuji, J. & Munekata, H. Investigation of spin voltaic effect in a p–n heterojunction. J. Appl. Phys. 45, L663–L665 (2006).

    Article  CAS  Google Scholar 

  19. Rangaraju, N., Peters, J. A. & Wessels, B. W. Magnetoamplification in a bipolar magnetic junction transistor. Phys. Rev. Lett. 105, 117202 (2010).

    Article  CAS  Google Scholar 

  20. Tulapurkar, A. A. et al. Spin-torque diode effect in magnetic tunnel junctions. Nature 438, 339–342 (2005).

    Article  CAS  Google Scholar 

  21. Sankey, J. C. et al. Spin-transfer-driven ferromagnetic resonance of individual nanomagnets. Phys. Rev. Lett. 96, 227601 (2006).

    Article  CAS  Google Scholar 

  22. Sankey, J. C., Cui, Y-T, Sun, J. Z., Slonczewski, J. C., Buhrman, R. A. & Ralph, D. C. Measurement of the spin-transfer-torque vector in magnetic tunnel junctions. Nature Phys. 4, 67–71 (2008).

    Article  CAS  Google Scholar 

  23. Kubota, H. et al. Quantitative measurement of voltage dependence of spin-transfer torque in MgO-based magnetic tunnel junctions. Nature Phys. 4, 37–41 (2008).

    Article  CAS  Google Scholar 

  24. Wang, C. et al. Bias and angular dependence of spin-torque in magnetic tunnel junctions. Phys. Rev. B 79, 224416 (2009).

    Article  Google Scholar 

  25. Wang, C., Cui, Y-T., Katine, J. A., Buhrman, R. A. & Ralph, D. C. Time-resolved measurement of spin-transfer-driven ferromagnetic resonance and spin torque in magnetic tunnel junctions. Nature Phys. 7, 496–501 (2011).

    Article  Google Scholar 

  26. Wang, C. et al. Sensitivity of spin-torque diodes for frequency-tunable resonant microwave detection. J. Appl. Phys. 106, 053905 (2009).

    Article  Google Scholar 

  27. Ishibashi, S. et al. Large diode sensitivity of CoFeB/MgO/CoFeB magnetic tunnel junctions. Appl. Phys. Express 3, 073001 (2010).

    Article  Google Scholar 

  28. Ishibashi, S. et al. High spin-torque diode sensitivity in CoFeB/MgO/CoFeB magnetic tunnel junctions under DC bias currents. IEEE Trans. Magn. 47, 3373–3376 (2011).

    Article  CAS  Google Scholar 

  29. Cheng, X., Boone, C. T., Zhu, J. & Krivorotov, I. N. Nonadiabatic stochastic resonance of a nanomagnet excited by spin torque. Phys. Rev. Lett. 105, 047202 (2010).

    Article  Google Scholar 

  30. Zhu, J. et al. Voltage-induced ferromagnetic resonance in magnetic tunnel junctions. Phys. Rev. Lett. 108, 197203 (2012).

    Article  Google Scholar 

  31. Kubota, H. et al. Enhancement of perpendicular magnetic anisotropy in FeB free layers using a thin MgO cap layer. J. Appl. Phys. 111, 07C723 (2012).

    Article  Google Scholar 

  32. Miwa, S. et al. Nonlinear thermal effect on sub-gigahertz ferromagnetic resonance in magnetic tunnel junction. Appl. Phys. Lett. 103, 042404.

    Article  Google Scholar 

  33. Petit, S. et al. Spin-torque influence on the high-frequency magnetization fluctuations in magnetic tunnel junctions. Phys. Rev. Lett. 98, 077203 (2007).

    Article  CAS  Google Scholar 

  34. Kim, J-V., Mistral, Q., Chappert, C., Tiberkevich, V. S. & Slavin, A. N. Line shape distortion in a nonlinear auto-oscillator near generation threshold: application to spin-torque nano-oscillators. Phys. Rev. Lett. 100, 167201 (2008).

    Article  Google Scholar 

  35. Lee, K-J., Deac, A., Redon, O., Nozières, J.-P. & Dieny, B. Excitations of incoherent spin-waves due to spin-transfer torque. Nature Mater. 3, 877–881 (2004).

    Article  CAS  Google Scholar 

  36. Nozaki, T. et al. Electric-field-induced ferromagnetic resonance excitation in an ultrathin ferromagnetic metal layer. Nature Phys. 8, 491 (2012).

    Article  Google Scholar 

  37. Zhang, S. & Zhang, S. S-L. Generalization of the Landau-Lifshitz-Gilbert equation for conducting ferromagnets. Phys. Rev. Lett. 102, 086601 (2009).

    Article  Google Scholar 

  38. Stutzke, N., Burkett, S. L. & Russek, S. E. Temperature and field dependence of high-frequency magnetic noise in spin valve devices. Appl. Phys. Lett. 82, 91–93 (2003).

    Article  CAS  Google Scholar 

  39. Prokopenko, O. et al. Noise properties of a resonance-type spin-torque microwave detector. Appl. Phys. Lett. 99, 032507 (2011).

    Article  Google Scholar 

  40. Maehara, H. et al. Tunnel magnetoresistance above 170% and resistance-area product of 1 Ω(μm)2 attained by in situ annealing of ultra-thin MgO tunnel barrier. Appl. Phys. Exp. 4, 033002 (2011).

    Article  Google Scholar 

  41. Emura, A. et al. 12th Joint MMM/Intermag Conf. BU-09 (IEEE Magnetic Society and The American Institute of Physics).

  42. Brown, W. F. Thermal fluctuations of a single-domain particle. Phys. Rev. 130, 1677–1686 (1963).

    Article  Google Scholar 

Download references

Acknowledgements

We thank A. A. Tulapurkar and S. Yakata for discussions. This research was conducted with the financial support of the Grant-in-Aid for Scientific Research (S), No. 23226001 from the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT).

Author information

Authors and Affiliations

Authors

Contributions

S.M. and S.I. performed the experiments and the analysis; they wrote the paper with T.N., N.M. and Y.S.’s appraisals and inputs. H.T. and S.M. conducted the simulations. S.I., T.S., H.K., K.Y., A.F. and S.Y. prepared the samples. E.T. and K.A. helped with the development of the theory and the measurements, respectively. T.T. and H.I conducted the theoretical analysis about the spin motive force. Y.S. conceived and designed the experiment and developed the theory. All authors contributed to the general discussion.

Corresponding author

Correspondence to Y. Suzuki.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 3127 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Miwa, S., Ishibashi, S., Tomita, H. et al. Highly sensitive nanoscale spin-torque diode. Nature Mater 13, 50–56 (2014). https://doi.org/10.1038/nmat3778

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nmat3778

This article is cited by

Search

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