Letter abstract


Nature Physics 6, 17 - 21 (2010)
Published online: 8 November 2009 | doi:10.1038/nphys1436

Subject Category: Electronics, photonics and device physics

Non-adiabatic spin-torques in narrow magnetic domain walls

C. Burrowes1,2, A. P. Mihai3,4, D. Ravelosona1,2, J.-V. Kim1,2, C. Chappert1,2, L. Vila3,4, A. Marty3,4, Y. Samson3, F. Garcia-Sanchez5, L. D. Buda-Prejbeanu5, I. Tudosa6, E. E. Fullerton6 & J.-P. Attané3,4

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Torques appear between charge carrier spins and local moments in regions of ferromagnetic media where spatial magnetization gradients occur, such as a domain wall, owing to an exchange interaction. This phenomenon has been predicted by different theories1, 2, 3, 4, 5, 6, 7 and confirmed in a number of experiments on metallic and semiconductor ferromagnets8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19. Understanding the magnitude and orientation of such spin-torques is an important problem for spin-dependent transport and current-driven magnetization dynamics, as domain-wall motion underlies a number of emerging spintronic technologies20, 21. One outstanding issue concerns the non-adiabatic spin-torque component β, which has an important role in wall dynamics, but no clear consensus has yet emerged over its origin or magnitude. Here, we report an experimental measurement of β in perpendicularly magnetized films with narrow domain walls (1–10nm). By studying thermally activated wall depinning, we deduce β from the variation of the Arrhenius transition rate with applied currents. Surprisingly, we find β to be small and relatively insensitive to the wall width, which stands in contrast to predictions from transport theories2, 5, 6, 7. In addition, we find β to be close to the Gilbert damping constant α, which, in light of similar results on planar anisotropy systems15, suggests a universal origin for the non-adiabatic torque.

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  1. Institut d’Electronique Fondamentale, CNRS, UMR 8622, 91405 Orsay, France
  2. Université Paris-Sud, 91405 Orsay, France
  3. CEA, Inac, SP2M, 38054 Grenoble, France
  4. Université Joseph Fourier, 38041 Grenoble, France
  5. SPINTEC, URA2512 CEA/CNRS/UJF/INPG, 38054 Grenoble, France
  6. Center for Magnetic Recording Research, University of California at San Diego, La Jolla, California 92093-0401, USA

Correspondence to: D. Ravelosona1,2 e-mail: dafine.ravelosona@u-psud.fr



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