Abstract
The magnetic state of a ferromagnet can affect the electrical transport properties of the material; for example, the relative orientation of the magnetic moments in magnetic multilayers1 underlies the phenomenon of giant magnetoresistance. The inverse effect—in which a large electrical current density can perturb the magnetic state of a multilayer—has been predicted2,3,4,5,6,7 and observed experimentally with point contacts8,9 and lithographically patterned samples10,11. Some of these observations were taken as indirect evidence for current-induced excitation of spin waves, or ‘magnons’. Here we probe directly the high-frequency behaviour and partial phase coherence of such current-induced excitations, by externally irradiating a point contact with microwaves. We determine the magnon spectrum and investigate how the magnon frequency and amplitude vary with the exciting current. Our observations support the feasibility of a spin-wave maser2 or ‘SWASER’ (spin-wave amplification by stimulated emission of radiation).
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
Baibich, M. N. et al. Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices. Phys. Rev. Lett. 61, 2472– 2475 (1988).
Berger, L. Emission of spin waves by a magnetic multilayer traversed by a current. Phys. Rev. B 54, 9353–9358 (1996).
Slonczewski, J. C. Current-driven excitation of magnetic multilayers. J. Magn. Magn. Mater. 159, L1–L7 ( 1996).
Berger, L. Multilayer as spin-wave emitting diodes. J. Appl. Phys. 81, 4880–4882 (1997).
Bazaliy, Ya. B., Jones, B. A. & Zhang, S.-C. Modification of the Landau-Lifshitz equation in the presence of a spin-polarized current in colossal- and giant-magnetoresistive materials. Phys. Rev. B 57, R3213– R3216 (1998).
Berger, L. Spin-wave emitting diodes and spin diffusion in magnetic multilayers. IEEE Trans. Magn. 34, 3837–3841 (1998).
Slonczewski, J. C. Excitation of spin waves by an electric current. J. Magn. Magn. Mater. 195, L261–L268 ( 1999).
Tsoi, M. et al. Excitation of a magnetic multilayer by an electric current. Phys. Rev. Lett. 80, 4281–4284 (1998).
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).
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. Preprint cond-mat/9908231 at 〈xxx.lanl.gov〉 (1999).
Sun, J. Z. Current-driven magnetic switching in manganite trilayer junctions. J. Magn. Magn. Mater. 202, 157–162 (1999).
Jansen, A. G. M., van Gelder, A. P. & Wyder, P. Point-contact spectroscopy in metals. J. Phys. C 13, 6073–6118 ( 1980).
Tsoi, M., Jansen, A. G. M. & Bass, J. Search for point-contact giant magnetoresistance in Co/Cu multilayers. J. Appl. Phys. 81, 5530 –5532 (1997).
Seck, M. & Wyder, P. A sensitive broadband high-frequency electron spin resonance/electron nuclear double resonance spectrometer operating at 5-7. 5 mm wavelength. Rev. Sci. Instrum. 69, 1817–1822 (1998).
van der Heijden, R. W., Jansen, A. G. M., Stoelinga, J. H. M., Swartjes, H. M. & Wyder, P. A new mechanism for high-frequency rectification at low temperatures in point contacts between identical metals. Appl. Phys. Lett. 37, 245–248 (1980).
Javan, A. in Fundamental and Applied Laser Physics (eds Field, M. S., Javan, A. & Kurnit, N. A.) 295–334 (Wiley, New York, 1973).
Seavey, M. H. Jr & Tannenwald, P. E. Direct observation of spin-wave resonance. Phys. Rev. Lett. 1, 168–169 (1958).
Herring, C. & Kittel, C. On the theory of spin waves in ferromagnetic media. Phys. Rev. 81, 869– 880 (1951).
Damon, R. W. & Eshbach, J. R. Magnetostatic modes of a ferromagnet slab. J. Phys. Chem. Solids 19, 308– 320 (1961).
Acknowledgements
This work was supported in part by the NSF, RU MNT, and RFFI.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Tsoi, M., Jansen, A., Bass, J. et al. Generation and detection of phase-coherent current-driven magnons in magnetic multilayers. Nature 406, 46–48 (2000). https://doi.org/10.1038/35017512
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/35017512
This article is cited by
-
Spintronics intelligent devices
Science China Physics, Mechanics & Astronomy (2023)
-
Current-driven magnetization reversal dynamics and breather-like EM soliton propagation in biaxial anisotropic weak ferromagnetic nanowire
Nonlinear Dynamics (2022)
-
Unconventional magnonic surface and interface states in layered ferromagnets
Communications Physics (2021)
-
Recent progress of radiation response in nanostructured tungsten for nuclear application
Tungsten (2021)
-
Microwave magnetic field modulation of spin torque oscillator based on perpendicular magnetic tunnel junctions
Scientific Reports (2019)
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.