MENU
  • Scitation Home
SUBMIT YOUR ARTICLE

Thank you

For your interest in the Journal of Applied Physics (JAP)

Check for updates on crossmark
Prev Next
Published Online: 09 February 2015
Accepted: October 2014

Resonant enhancement of damping within the free layer of a microscale magnetic tunnel valve

Journal of Applied Physics 117, 17B301 (2015); https://doi.org/10.1063/1.4907701
P. S. Keatley1, a), V. V. Kruglyak1, A. Neudert1,2, R. J. Hicken1, V. D. Poimanov3, J. R. Childress4, and J. A. Katine4
more...View Affiliations
Abstract
Picosecond magnetization dynamics in the free and pinned layers of a microscale magnetic tunnel valve have been studied using time-resolved scanning Kerr microscopy. A comparison of the observed dynamics with those of individual free and pinned layers allowed the effect of interlayer coupling to be identified. A weak interlayer coupling in the tunnel valve continuous film reference sample was detected in bulk magnetometry measurements, while focused Kerr magnetometry showed that the coupling was well maintained in the patterned structure. In the tunnel valve, the free layer precession was observed to have reduced amplitude and an enhanced relaxation. During magnetization reversal in the pinned layer, its frequency approached that of the low frequency mode associated with the free layer. At the pinned layer switching field, the linewidth of the free layer became similar to that of the pinned layer. The similarity in their frequencies promotes the formation of precessional modes that exhibit strong collective properties such as frequency shifting and enhanced linewidth, while inhomogeneous magnetization of the pinned layer during reversal may also play a role in these observations. The collective character of precessional dynamics associated with mixing of the free and pinned layer magnetization dynamics must be accounted for even in tunnel valves with a small interlayer coupling.
The authors gratefully acknowledge financial support from the UK Engineering and Physical Sciences Research Council Grant Nos. EP/C52022X/1, EP/D000572/1, and EP/I038470/1, and from the European Community's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement No. 247556 (NoWaPhen).

References

  1. 1. I. N. Krivorotov, N. C. Emley, J. C. Sankey, S. I. Kiselev, D. C. Ralph, and R. A. Buhrman, Science 307, 228 (2005). https://doi.org/10.1126/science.1105722, Google ScholarCrossref
  2. 2. T. Gerrits, H. A. M. van den Berg, J. Hohlfeld, L. Bar, and T. Rasing, Nature 418, 509 (2002). https://doi.org/10.1038/nature00905, Google ScholarCrossref
  3. 3. N. Smith, M. J. Carey, and J. R. Childress, Phys. Rev. B 81, 184431 (2010). https://doi.org/10.1103/PhysRevB.81.184431, Google ScholarCrossref
  4. 4. G. Woltersdorf, O. Mosendz, B. Heinrich, and C. H. Back, Phys. Rev. Lett. 99, 246603 (2007). https://doi.org/10.1103/PhysRevLett.99.246603, Google ScholarCrossref
  5. 5. J. R. Childress, M. M. Schwickert, R. E. Fontana, M. K. Ho, P. M. Rice, and B. A. Gurney, J. Appl. Phys. 89, 7353 (2001). https://doi.org/10.1063/1.1361050, Google ScholarScitation
  6. 6. P. S. Keatley, V. V. Kruglyak, A. Neudert, E. A. Galaktionov, R. J. Hicken, J. R. Childress, and J. A. Katine, Phys. Rev. B 78, 214412 (2008). https://doi.org/10.1103/PhysRevB.78.214412, Google ScholarCrossref
  7. 7. J. H. H. Rietjens, C. Józsa, W. J. M. de Jonge, B. Koopmans, and H. Boeve, Appl. Phys. Lett. 87, 172508 (2005). https://doi.org/10.1063/1.2117614, Google ScholarScitation
  8. 8. J. H. H. Rietjens, C. Jozsa, H. Boeve, W. J. M. de Jonge, and B. Koopmans, J. Magn. Magn. Mater. 290–291, 494 (2005). https://doi.org/10.1016/j.jmmm.2004.11.510, Google ScholarCrossref
  9. 9. P. S. Keatley, V. V. Kruglyak, R. J. Hicken, J. R. Childress, and J. A. Katine, J. Magn. Magn. Mater. 306, 298 (2006). https://doi.org/10.1016/j.jmmm.2006.03.030, Google ScholarCrossref
  10. 10. B. D. Schrag, A. Anguelouch, G. Xiao, P. Trouilloud, Y. Lu, W. J. Gallagher, and S. S. P. Parkin, J. Appl. Phys. 87, 4682 (2000). https://doi.org/10.1063/1.373129, Google ScholarScitation
  11. 11. V. V. Kruglyak, A. Barman, R. J. Hicken, J. R. Childress, and J. A. Katine, Phys. Rev. B 71, 220409(R) (2005). https://doi.org/10.1103/PhysRevB.71.220409, Google ScholarCrossref
  12. 12.Cavity enhancement of the Kerr rotation using a ZnS (33 nm) layer was used on the TV stack. The Kerr rotation has been scaled appropriately for comparison with the uncapped FL and PL reference discs.
  13. 13.The same FL data are shown in Figures 3(a) and 3(b) since the FL frequency dependance is not expected to depend on the magnetic field sweep direction when the applied field is larger than the anisotropy field.
  14. 14. J. F. Sierra, F. G. Aliev, R. Heindl, S. E. Russek, and W. H. Rippard, Appl. Phys. Lett. 94, 012506 (2009). https://doi.org/10.1063/1.3054642, Google ScholarScitation
  15. 15. X. Joyeux, T. Devolder, J.-V. Kim, Y. Gomez de la Torre, S. Eimer, and C. Chappert, J. Appl. Phys. 110, 063915 (2011). https://doi.org/10.1063/1.3638055, Google ScholarScitation
  16. 16. A. M. Zyuzin, A. G. Bazhanov, S. N. Sabaev, and S. S. Kidyaev, Phys. Solid State 42, 1317 (2000). https://doi.org/10.1134/1.1131385, Google ScholarCrossref
  17. 17. V. V. Kruglyak and A. N. Kuchko, Phys. Met. Metall. 92, 211 (2001). Google Scholar
  18. © 2015 AIP Publishing LLC.

Article Metrics

Views
51
Citations
Crossref 1
Web of Science
ISI 2

Altmetric

Please Note: The number of views represents the full text views from December 2016 to date. Article views prior to December 2016 are not included.