Abstract
Spin-momentum transfer between a spin-polarized current and a ferromagnetic layer can induce steady-state magnetization precession, and has recently been proposed as a working principle for ubiquitous radio-frequency devices for radar and telecommunication applications. However, so far, the development of industrially attractive prototypes has been hampered by the inability to identify systems that can provide enough power. Here, we demonstrate that microwave signals with device-compatible output power levels can be generated from a single magnetic tunnel junction with a lateral size of 100 nm, seven orders of magnitude smaller than conventional radio-frequency oscillators. We find that in MgO magnetic tunnel junctions the perpendicular torque induced by the spin-polarized current on the local magnetization can reach 25% of the in-plane spin-torque term, although showing a different bias dependence. Both findings contrast with the results obtained on all-metallic structures, previously investigated, reflecting the fundamentally different transport mechanisms in the two types of structure.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
$209.00 per year
only $17.42 per issue
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
Similar content being viewed by others
References
Slonczewski, J. C. Current-driven excitations 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).
Kiselev, S. I. et al. Microwave oscillations of a nanomagnet driven by a spin-polarized current. Nature 425, 380–382 (2003).
Covington, M., AlHajDarwish, M., Ding, Y., Gokemeijer, N. J. & Seigler, M. A. Current-induced magnetization dynamics in current perpendicular to the plane spin valves. Phys. Rev. B 69, 184406 (2004).
Deac, A. et al. Study of spin-transfer-induced dynamics in spin-valves for current-perpendicular-to-plane magnetoresistive heads. J. Phys.: Condens. Matter 19, 165208 (2007).
Krivorotov, I. N. et al. Time-domain measurements of nanomagnet dynamics driven by spin-transfer torques. Science 307, 228–231 (2005).
Kaka, S. et al. Mutual phase-locking of microwave spin-torque nano-oscillators. Nature 437, 389–392 (2005).
Mancoff, F. B., Rizzo, N. D., Engel, B. N. & Tehrani, S. Phase-locking in double-point-contact spin-transfer devices. Nature 437, 393–395 (2005).
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).
Rippard, W. H., Puffal, M. R., Kaka, S., Russek, S. E. & Silva, T. J. Direct-current induced dynamics in Co90Fe10/Ni80Fe20 point contacts. Phys. Rev. Lett. 92, 027201 (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).
Parkin, S. S. P. et al. Giant tunnelling magnetoresistance at room temperature with MgO (100) barriers. Nature Mater. 3, 862–867 (2004).
Yuasa, S., Fukushima, A., Kubota, H. & Ando, K. Giant tunneling magnetoresistance up to 410% at room temperature in fully epitaxial Co/MgO/Co tunnel junctions with bcc Co(001) electrodes. Appl. Phys. Lett. 89, 042505 (2006).
Hayakawa, J., Ikeda, S., Lee, Y. M., Matsukura, F. & Ohno, H. Effect of high annealing temperature on giant tunnel magnetoresistance ratio of CoFeB/MgO/CoFeB magnetic tunnel junctions. Appl. Phys. Lett. 89, 232510 (2006).
Slonczewski, J. C. & Sun, J. Theory of voltage-driven current and torque in magnetic tunnel junctions. J. Magn. Magn. Mater. 310, 169–175 (2007).
Theodonis, I., Kioussis, N., Kalitsov, A., Chshiev, M. & Butler, W. H. Anomalous bias dependence of spin-torque in magnetic tunnel junctions. Phys. Rev. Lett. 97, 237206 (2006).
Kubota, H. et al. Quantitative measurement of voltage dependence of spin-transfer torque in MgO-based magnetic tunnel juntions. Nature Phys. 4, 37–41 (2008).
Sankey, J. K. et al. Measurement of the spin-transfer-torque vector in magnetic tunnel junctions. Nature Phys. 4, 67–71 (2008).
Nazarov, A. V. et al. Spin transfer stimulated microwave emission in MgO magnetic tunnel junctions. Appl. Phys. Lett. 88, 162504 (2006).
Myers, E. B. et al. Thermally activated magnetic reversal induced by a spin-polarized current. Phys. Rev. Lett. 89, 196801 (2002).
Zimmler, M. A. et al. Current-induced effective magnetic fields in Co/Cu/Co nanopillars. Phys. Rev. B 70, 184438 (2004).
Kubota, H. et al. Dependence of spin-transfer switching current on free layer thickness in Co–Fe–B/MgO/Co–Fe–B magnetic tunnel junctions. Appl. Phys. Lett. 89, 032505 (2006).
Tsunekawa, K. et al. Giant tunnelling magnetoresistance effect in low-resistance CoFeB/MgO(001)/CoFeB magnetic tunnel junctions for read-head applications. Appl. Phys. Lett. 87, 072503 (2005).
Kittel, C. Introduction to Solid State Physics 7th edn, 505 (Wiley, New York, 1996).
McMichael, R. D. & Stiles, M. D. Magnetic normal modes of nanoelements. J. Appl. Phys. 97, 10J901 (2005).
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).
Lee, K. -J., Deac, A., Redon, O, Nozieres, J. -P. & Dieny, B. Excitations of incoherent spin-waves due to spin-transfer torque. Nature Mater. 3, 877–881 (2004).
Zhu, J. G. & Zhu, X. C. Spin transfer induced noise in CPP read heads. IEEE Trans. Magn. 40, 182–188 (2004).
Petit, S. et al. Spin-torque influence on the high-frequency magnetization fluctuations in magnetic tunnel junctions. Phys. Rev. Lett. 98, 077203 (2007).
Fuchs, G. D. et al. Spin-torque ferromagnetic resonance measurements of damping in nanomagnets. Appl. Phys. Lett. 91, 062507 (2007).
Bilzer, C. Study of dynamic magnetic properties of soft CoFeB films. J. Appl. Phys. 100, 053903 (2006).
Matsumoto, R. et al. Tunneling spectra of sputter-deposited CoFeB/MgO/CoFeB magnetic tunnel junctions showing giant tunneling magnetoresistance effect. Solid State Commun. 136, 611–615 (2005).
Matsumoto, R. et al. Dependence on annealing temperatures of tunneling spectra in high-resistance CoFeB/MgO/CoFeB magnetic tunnel junctions. Solid State Commun. 143, 574–578 (2007).
Slonczewski, J. C. Currents, torques, and polarization factors in magnetic tunnel junctions. Phys. Rev. B 71, 024411 (2005).
Zhu, J. G. Thermal magnetic noise and spectra in spin valve heads. J. Appl. Phys. 91, 7273–7275 (2002).
Acknowledgements
The authors thank J. C. Slonczewski, G. E. W. Bauer, T. J. Silva, S. E. Russek, M. Mizuguchi, R. Jansen and J. M. Shaw for discussions. This research was partially supported by SCOPE-MIC and MEXT. A.M.D. acknowledges support from the Japan Society for the Promotion of Science through the research grant P05330.
Author information
Authors and Affiliations
Contributions
A.M.D. carried out the measurements, analysed the data and wrote the paper. A.F. and H.K. developed the patterning process and fabricated the samples. A.F. also provided considerable help with the experimental set-up. H.K., Y.N., K.T., D.D.D. and N.W. optimized the sputtering process for low-R A MgO magnetic tunnel junctions and deposited the multilayers. S.Y. helped develop the magnetic tunnel junction and carried out studies for increasing the TMR. Y.S. helped with analysing the data and calculated the losses in the system. All authors discussed the result and commented on the manuscript.
Corresponding author
Supplementary information
Supplementary Information
Supplementary Information, Supplementary Figures 1—8 and Supplementary Table 1 (PDF 732 kb)
Rights and permissions
About this article
Cite this article
Deac, A., Fukushima, A., Kubota, H. et al. Bias-driven high-power microwave emission from MgO-based tunnel magnetoresistance devices. Nature Phys 4, 803–809 (2008). https://doi.org/10.1038/nphys1036
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nphys1036
This article is cited by
-
Elongated skyrmion as spin torque nano-oscillator and magnonic waveguide
Communications Physics (2022)
-
Observation of magnetic droplets in magnetic tunnel junctions
Science China Physics, Mechanics & Astronomy (2022)
-
Spin-Filter Devices Based on Resonant Magnetic Tunnel Junctions
Journal of Electronic Materials (2021)
-
Spin–orbit torque nano-oscillator with giant magnetoresistance readout
Communications Physics (2020)
-
Tunnel magnetoresistance angular and bias dependence enabling tuneable wireless communication
Scientific Reports (2019)