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
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Baibich, M. N. et al. Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices. Phys. Rev. Lett. 61, 2472–2475 (1988).
Miyazaki, T. & Tezuka, N. Giant magnetic tunneling effect in Fe/Al2O3/Fe junction. J. Magn. Magn. Mater. 139, L231–L234 (1995).
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).
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).
Parkin, S. S. P. et al. Giant tunneling magnetoresistance at room temperature with MgO (100) tunnel barriers. Nature Mater. 3, 862–867 (2004).
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).
Djayaprawira, D. D. et al. 230% room-temperature magnetoresistance in CoFeB/MgO/CoFeB magnetic tunnel junctions. Appl. Phys. Lett. 86, 092502 (2005).
Slonczewski, J. C. Current-driven excitation of magnetic multilayers. J. Magn. Magn. Mater. 159, L1–L7 (1996).
Berger, L. Emission of spin waves by a magnetic multilayer traversed by a current. Phys. Rev. B 54, 9353–9358 (1996).
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).
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).
Kubota, H. et al. Evaluation of spin-transfer switching in CoFeB/MgO/CoFeB magnetic tunnel junctions. Jpn. J. Appl. Phys. 44, L1237–L1240 (2005).
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).
Tsoi, M. et al. Excitation of a magnetic multilayer by an electric current. Phys. Rev. Lett. 80, 4281–4284 (1998).
Kiselev, S. et al. Microwave oscillations of a nanomagnet driven by a spin-polarized current. Nature 425, 380–382 (2003).
Deac, A. et al. Bias-driven high-power microwave emission from MgO-based tunnel magnetoresistance devices. Nature Phys. 4, 803–809 (2008).
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).
Kondo, T., Hayafuji, J. & Munekata, H. Investigation of spin voltaic effect in a p–n heterojunction. J. Appl. Phys. 45, L663–L665 (2006).
Rangaraju, N., Peters, J. A. & Wessels, B. W. Magnetoamplification in a bipolar magnetic junction transistor. Phys. Rev. Lett. 105, 117202 (2010).
Tulapurkar, A. A. et al. Spin-torque diode effect in magnetic tunnel junctions. Nature 438, 339–342 (2005).
Sankey, J. C. et al. Spin-transfer-driven ferromagnetic resonance of individual nanomagnets. Phys. Rev. Lett. 96, 227601 (2006).
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).
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).
Wang, C. et al. Bias and angular dependence of spin-torque in magnetic tunnel junctions. Phys. Rev. B 79, 224416 (2009).
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).
Wang, C. et al. Sensitivity of spin-torque diodes for frequency-tunable resonant microwave detection. J. Appl. Phys. 106, 053905 (2009).
Ishibashi, S. et al. Large diode sensitivity of CoFeB/MgO/CoFeB magnetic tunnel junctions. Appl. Phys. Express 3, 073001 (2010).
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).
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).
Zhu, J. et al. Voltage-induced ferromagnetic resonance in magnetic tunnel junctions. Phys. Rev. Lett. 108, 197203 (2012).
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).
Miwa, S. et al. Nonlinear thermal effect on sub-gigahertz ferromagnetic resonance in magnetic tunnel junction. Appl. Phys. Lett. 103, 042404.
Petit, S. et al. Spin-torque influence on the high-frequency magnetization fluctuations in magnetic tunnel junctions. Phys. Rev. Lett. 98, 077203 (2007).
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).
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).
Nozaki, T. et al. Electric-field-induced ferromagnetic resonance excitation in an ultrathin ferromagnetic metal layer. Nature Phys. 8, 491 (2012).
Zhang, S. & Zhang, S. S-L. Generalization of the Landau-Lifshitz-Gilbert equation for conducting ferromagnets. Phys. Rev. Lett. 102, 086601 (2009).
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).
Prokopenko, O. et al. Noise properties of a resonance-type spin-torque microwave detector. Appl. Phys. Lett. 99, 032507 (2011).
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).
Emura, A. et al. 12th Joint MMM/Intermag Conf. BU-09 (IEEE Magnetic Society and The American Institute of Physics).
Brown, W. F. Thermal fluctuations of a single-domain particle. Phys. Rev. 130, 1677–1686 (1963).
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
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
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary Information
Supplementary Information (PDF 3127 kb)
Rights 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
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nmat3778
This article is cited by
-
Nonlinear amplification of microwave signals in spin-torque oscillators
Nature Communications (2023)
-
Electrically connected spin-torque oscillators array for 2.4 GHz WiFi band transmission and energy harvesting
Nature Communications (2021)
-
Uncooled sub-GHz spin bolometer driven by auto-oscillation
Nature Communications (2021)
-
Digital and analogue modulation and demodulation scheme using vortex-based spin torque nano-oscillators
Scientific Reports (2020)
-
Influence of flicker noise and nonlinearity on the frequency spectrum of spin torque nano-oscillators
Scientific Reports (2020)