Abstract
Spin-transfer1,2 in nanometre-scale magnetic devices results from the torque on a ferromagnet owing to its interaction with a spin-polarized current and the electrons' spin angular momentum. Experiments have detected either a reversal3,4,5,6,7,8,9,10,11,12,13,14,15,16 or high-frequency (GHz) steady-state precession17,18,19,20,21,22,23 of the magnetization in giant magnetoresistance spin valves and magnetic tunnel junctions with current densities of more than 107 A cm-2. Spin-transfer devices may enable high-density, low-power magnetic random access memory24,25 or direct-current-driven nanometre-sized microwave oscillators. Here we show that the magnetization oscillations induced by spin-transfer in two 80-nm-diameter giant-magnetoresistance point contacts in close proximity to each other can phase-lock into a single resonance over a frequency range from approximately <10 to >24 GHz for contact spacings of less than about ∼200 nm. The output power from these contact pairs with small spacing is approximately twice the total power from more widely spaced (∼400 nm and greater) contact pairs that undergo separate resonances, indicating that the closely spaced pairs are phase-locked with zero phase shift. Phase-locking may enable control of large arrays of coupled spin-transfer devices with increased power output for microwave oscillator applications.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- 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
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. N. & Buhrman, R. A. Current-induced switching of domains in magnetic multilayer devices. Science 285, 867–870 (1999)
Wegrowe, J.-E., Kelly, D., Jaccard, Y., Guittienne, Ph. & Ansermet, J.-Ph. Current-induced magnetization reversal in magnetic nanowires. Europhys. Lett. 45, 626–632 (1999)
Katine, J. A., Albert, F. J., Buhrman, R. A., Myers, E. B. & Ralph, D. C. Current-driven magnetization reversal and spin-wave excitations in Co/Cu/Co pillars. Phys. Rev. Lett. 84, 3149–3152 (2000)
Grollier, J. et al. Spin-polarized current induced switching in Co/Cu/Co pillars. Appl. Phys. Lett. 78, 3663–3665 (2001)
Sun, J. Z., Monsma, D. J., Abraham, D. W., Rooks, M. J. & Koch, R. H. Batch-fabricated spin-injection magnetic switches. Appl. Phys. Lett. 81, 2202–2204 (2002)
Urazhdin, S., Birge, N. O., Pratt, W. P. Jr & Bass, J. Current-driven magnetic excitations in permalloy-based multilayer nanopillars. Phys. Rev. Lett. 91, 146803 (2003)
Mancoff, F. B. et al. Angular dependence of spin-transfer switching in a magnetic nanostructure. Appl. Phys. Lett. 83, 1596–1598 (2003)
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)
Ozyilmaz, B. et al. Current-induced magnetization reversal in high magnetic fields in Co/Cu/Co nanopillars. Phys. Rev. Lett. 91, 067203 (2003)
Yagami, K., Tulapurkar, A. A., Fukushima, A. & Suzuki, Y. Low-current spin-transfer switching and its thermal durability in a low-saturation-magnetization nanomagnet. Appl. Phys. Lett. 85, 5634–5636 (2004)
Jiang, Y. et al. Substantial reduction of critical current for magnetization switching in an exchange-biased spin valve. Nature Mater. 3, 361–363 (2004)
Chen, T. Y., Ji, Y., Chien, C. L. & Stiles, M. D. Current-driven switching in a single exchange-biased ferromagnetic layer. Phys. Rev. Lett. 93, 026601 (2004)
Lacour, D., Katine, J. A., Smith, N., Carey, M. J. & Childress, J. R. Thermal effects on the magnetic-field dependence of spin-transfer-induced magnetization reversal. Appl. Phys. Lett. 85, 4681–4683 (2004)
Lee, K. J. et al. Spin transfer effect in spin-valve pillars for current-perpendicular-to-plane magnetoresistive heads. J. Appl. Phys. 95, 7423–7428 (2004)
Tsoi, M. et al. Generation and detection of phase-coherent current-driven magnons in magnetic multilayers. Nature 406, 46–48 (2000)
Kiselev, S. I. et al. Microwave oscillations of a nanomagnet driven by a spin-polarized current. Nature 425, 380–383 (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)
Rippard, W. H., Pufall, 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)
Kiselev, S. I. et al. Current-induced nanomagnet dynamics for magnetic fields perpendicular to the sample plane. Phys. Rev. Lett. 93, 036601 (2004)
Rippard, W. H., Pufall, M. R., Kaka, S., Silva, T. J. & Russek, S. E. Current-driven microwave dynamics in magnetic point contacts as a function of applied field angle. Phys. Rev. B 70, 100406 (2004)
Krivorotov, I. N. et al. Time-domain measurements of nanomagnet dynamics driven by spin-transfer torques. Science 307, 228–231 (2005)
Engel, B. N. et al. A 4-Mbit toggle MRAM based on a novel bit and switching method. IEEE Trans. Mag. 41, 132–136 (2005)
Parkin, S. S. P. et al. Exchange-biased magnetic tunnel junctions and application to nonvolatile magnetic random access memory. J. Appl. Phys. 85, 5828–5833 (1999)
Russek, S. E., Kaka, S., Rippard, W. H., Pufall, M. R. & Silva, T. J. Finite-temperature modeling of nanoscale spin-transfer oscillators. Phys. Rev. B 71, 104425 (2005)
Acknowledgements
We thank W. H. Rippard, T. J. Silva and S. E. Russek for discussions. This work was supported in part by the DARPA SPINS programme through Motorola.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Competing interests
Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.
Rights and permissions
About this article
Cite this article
Mancoff, F., Rizzo, N., Engel, B. et al. Phase-locking in double-point-contact spin-transfer devices. Nature 437, 393–395 (2005). https://doi.org/10.1038/nature04036
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/nature04036
This article is cited by
-
Non-hermiticity in spintronics: oscillation death in coupled spintronic nano-oscillators through emerging exceptional points
Nature Communications (2024)
-
Second harmonic injection locking of coupled spin torque vortex oscillators with an individual phase access
Communications Physics (2023)
-
Spintronics intelligent devices
Science China Physics, Mechanics & Astronomy (2023)
-
Binding events through the mutual synchronization of spintronic nano-neurons
Nature Communications (2022)
-
Ultra-wide-band millimeter-wave generator using spin torque oscillator with strong interlayer exchange couplings
Scientific Reports (2022)
Comments
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.