Abstract
The energy bandgap of an insulator is large enough to prevent electron excitation and electrical conduction1. But in addition to charge, an electron also has spin2, and the collective motion of spin can propagate—and so transfer a signal—in some insulators3. This motion is called a spin wave and is usually excited using magnetic fields. Here we show that a spin wave in an insulator can be generated and detected using spin-Hall effects, which enable the direct conversion of an electric signal into a spin wave, and its subsequent transmission through (and recovery from) an insulator over macroscopic distances. First, we show evidence for the transfer of spin angular momentum between an insulator magnet Y3Fe5O12 and a platinum film. This transfer allows direct conversion of an electric current in the platinum film to a spin wave in the Y3Fe5O12 via spin-Hall effects4,5,6,7,8,9,10,11. Second, making use of the transfer in a Pt/Y3Fe5O12/Pt system, we demonstrate that an electric current in one metal film induces voltage in the other, far distant, metal film. Specifically, the applied electric current is converted into spin angular momentum owing to the spin-Hall effect7,8,10,11 in the first platinum film; the angular momentum is then carried by a spin wave in the insulating Y3Fe5O12 layer; at the distant platinum film, the spin angular momentum of the spin wave is converted back to an electric voltage. This effect can be switched on and off using a magnetic field. Weak spin damping3 in Y3Fe5O12 is responsible for its transparency for the transmission of spin angular momentum. This hybrid electrical transmission method potentially offers a means of innovative signal delivery in electrical circuits and devices.
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References
Ashcroft, N. W. & Mermin, N. D. Solid State Physics Ch. 9 (Saunders College, 1976)
Maekawa, S. ed. Concepts in Spin Electronics Ch. 7 and 8 (Oxford Univ. Press, 2006)
Schneider, T. et al. Realization of spin-wave logic gates. Appl. Phys. Lett. 92, 022505 (2008)
Dyakonov, M. I. & Perel, V. I. Current-induced spin orientation of electrons in semiconductors. Phys. Lett. A 35, 459–460 (1971)
Hirsch, J. E. Spin Hall effect. Phys. Rev. Lett. 83, 1834–1837 (1999)
Takahashi, S. & Maekawa, S. Hall effect induced by a spin-polarized current in superconductors. Phys. Rev. Lett. 88, 116601 (2002)
Kato, Y. K., Myers, R. C., Gossard, A. C. & Awschalom, D. D. Observation of the spin Hall effect in semiconductors. Science 306, 1910–1913 (2004)
Wunderlich, J., Kaestner, B., Sinova, J. & Jungwirth, T. Experimental observation of the spin-Hall effect in a two-dimensional spin-orbit coupled semiconductor system. Phys. Rev. Lett. 94, 047204 (2005)
Saitoh, E., Ueda, M., Miyajima, H. & Tatara, G. Conversion of spin current into charge current at room temperature: inverse spin-Hall effect. Appl. Phys. Lett. 88, 182509 (2006)
Valenzuela, S. O. & Tinkham, M. Direct electronic measurement of the spin Hall effect. Nature 442, 176–179 (2006)
Kimura, T., Otani, Y., Sato, T., Takahashi, S. & Maekawa, S. Room-temperature reversible spin Hall effect. Phys. Rev. Lett. 98, 156601 (2007)
Valet, T. & Fert, A. Theory of the perpendicular magnetoresistance in magnetic multilayers. Phys. Rev. B 48, 7099–7113 (1993)
Takahashi, S. & Maekawa, S. Spin current in metals and superconductors. J. Phys. Soc. Jpn 77, 031009 (2008)
Kittel, C. Introduction to Solid State Physics 8th edn, Ch. 12 and 13 (Wiley, 2005)
Demokritov, S. O., Hillebrands, B. & Slavin, A. N. Brillouin light scattering studies of confined spin waves: linear and nonlinear confinement. Phys. Rep. 348, 441–489 (2001)
Bass, J. & Pratt, W. P. Spin-diffusion lengths in metals and alloys, and spin-flipping at metal/metal interfaces: an experimentalist’s critical review. J. Phys. Condens. Matter 19, 183201 (2007)
Silsbee, R. H., Janossy, A. & Monod, P. Coupling between ferromagnetic and conduction-spin-resonance modes at a ferromagnetic-normal-metal interface. Phys. Rev. B 19, 4382–4399 (1979)
Tserkovnyak, Y., Brataas, A. & Bauer, G. E. W. Enhanced Gilbert damping in thin ferromagnetic films. Phys. Rev. Lett. 88, 117601 (2002)
Mizukami, S., Ando, Y. & Miyazaki, T. Effect of spin diffusion on Gilbert damping for a very thin permalloy layer in Cu/permalloy/Cu/Pt films. Phys. Rev. B 66, 104413 (2002)
Kiselev, S. I. et al. Microwave oscillations of a nanomagnet driven by a spin-polarized current. Nature 425, 380–383 (2003)
Ji, Y., Chien, C. L. & Stiles, M. D. Current-induced spin-wave excitations in a single ferromagnetic layer. Phys. Rev. Lett. 90, 106601 (2003)
Ando, K. et al. Electric manipulation of spin relaxation using the spin Hall effect. Phys. Rev. Lett. 101, 036601 (2008)
Brataas, A., Bauer, G. E. W. & Kelly, P. J. Non-collinear magnetoelectronics. Phys. Rep. 427, 157–255 (2006)
Chikazumi, S. Physics of Ferromagnetism Ch. 20 and 21 (Oxford Univ. Press, 1997)
Stiles, M. D., Xiao, J. & Zangwill, A. Phenomenological theory of current-induced magnetization precession. Phys. Rev. B 69, 054408 (2004)
Wigen, P. E., Doetsch, H., Ming, Y., Baselgia, L. & Waldner, F. Chaos in magnetic garnet thin films. J. Appl. Phys. 63, 4157–4159 (1988)
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)
Krivorotov, I. N. et al. Large-amplitude coherent spin waves excited by spin-polarized current in nanoscale spin valves. Phys. Rev. B 76, 024418 (2007)
Laulicht, I., Suss, J. T. & Barak, J. The temperature dependence of the ferromagnetic and paramagnetic resonance spectra in thin yttrium-iron-garnet films. J. Appl. Phys. 70, 2251–2258 (1991)
Brown, W. F. Thermal fluctuations of a single-domain particle. Phys. Rev. 130, 1677–1686 (1963)
Donahue, M. J. & Porter, D. G. OOMMF v1.2a3 Object Oriented MicroMagnetic Framework Software (NIST, 2004)
Acknowledgements
We thank K. Sato, Y. Suzuki, Y. Tserkovnyak, G. Tatara, T. Ishibashi and K. M. Itoh for discussions. This work was supported by a Grant-in-Aid for Scientific Research in Priority Area ‘Creation and control of spin current’ (19048028) from MEXT, Japan, a Grant-in-Aid for Scientific Research (A) from MEXT, Japan, the global COE for the ‘Materials integration international centre of education and research’ and ‘High-level global cooperation for leading-edge platform on access spaces (C12)’ from MEXT, Japan, a Grant for Industrial Technology Research from NEDO, Japan, and Fundamental Research Grant from TRF, Japan.
Author Contributions Y.K., K.H., K.U. and K.A. performed the measurements and analysed the data; J.O. carried out the numerical analysis; S.T., S.M. and E.S. provided the theoretical analysis; H.U. and H.K. contributed to the sample fabrication; Y.K., K.H, K.U., M.M. and K.T. contributed to the experimental set-up; Y.K., S.T., J.O., K.U., M.M., H.U., K.T., S.M. and E.S. wrote the manuscript; all authors discussed the results and commented on the manuscript; and E.S. planned and supervised the project.
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Kajiwara, Y., Harii, K., Takahashi, S. et al. Transmission of electrical signals by spin-wave interconversion in a magnetic insulator. Nature 464, 262–266 (2010). https://doi.org/10.1038/nature08876
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DOI: https://doi.org/10.1038/nature08876
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