Published Online: 07 November 2016
Accepted: October 2016
Appl. Phys. Lett. 109, 192404 (2016); https://doi.org/10.1063/1.4967318
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We introduce a differential planar Hall effect method that enables the experimental study of spin orbit torque switching of in-plane magnetized free layers in a simple Hall bar device geometry. Using this method, we study the Pt thickness dependence of switching currents and show that they decrease monotonically down to the minimum experimental thickness of ∼5 nm, while the critical current and power densities are very weakly thickness dependent, exhibiting the minimum values of Jc0 = 1.1 × 108 A/cm2 and ρJc02=0.6×1012W/cm3 at this minimum thickness. Our results suggest that a significant reduction of the critical parameters could be achieved by optimizing the free layer magnetics, which makes this technology a viable candidate for fast, high endurance and low-error rate applications such as cache memories.
  1. 1. A. Manchon and S. Zhang, Phys. Rev. B 78, 212405 (2008). https://doi.org/10.1103/PhysRevB.78.212405, Google ScholarCrossref
  2. 2. A. Manchon and S. Zhang, Phys. Rev. B 79, 094422 (2009). https://doi.org/10.1103/PhysRevB.79.094422, Google ScholarCrossref
  3. 3. I. M. Miron, G. Gaudin, S. Auffret, B. Rodmacq, A. Schuhl, S. Pizzini, J. Vogel, and P. Gambardella, Nat. Mater. 9, 230 (2010). https://doi.org/10.1038/nmat2613, Google ScholarCrossref
  4. 4. I. M. Miron, K. Garello, G. Gaudin, P. Zermatten, M. V. Costache, S. Auffret, S. Bandiera, B. Rodmacq, A. Schuhl, and P. Gambardella, Nature 476, 189 (2011). https://doi.org/10.1038/nature10309, Google ScholarCrossref
  5. 5. L. Liu, O. J. Lee, T. J. Gudmundsen, D. C. Ralph, and R. A. Buhrman, Phys. Rev. Lett. 109, 096602 (2012). https://doi.org/10.1103/PhysRevLett.109.096602, Google ScholarCrossref
  6. 6. L. Liu, C.-F. Pai, Y. Li, H. W. Tseng, D. C. Ralph, and R. A. Buhrman, Science 336, 555 (2012). https://doi.org/10.1126/science.1218197, Google ScholarCrossref
  7. 7. J. C. Slonczewski, J. Magn. Magn. Mater. 159, L1 (1996). https://doi.org/10.1016/0304-8853(96)00062-5, Google ScholarCrossref
  8. 8. L. Berger, Phys. Rev. B 54, 9353 (1996). https://doi.org/10.1103/PhysRevB.54.9353, Google ScholarCrossref
  9. 9. C. Chappert, A. Fert, and F. N. Van Dau, Nat. Mater. 6, 813 (2007). https://doi.org/10.1038/nmat2024, Google ScholarCrossref
  10. 10. D. C. Ralph and M. D. Stiles, J. Magn. Magn. Mater. 320, 1190 (2008). https://doi.org/10.1016/j.jmmm.2007.12.019, Google ScholarCrossref
  11. 11. T. Kawahara, K. Ito, R. Takemura, and H. Ohno, Microelectron. Reliab. 52, 613 (2012). https://doi.org/10.1016/j.microrel.2011.09.028, Google ScholarCrossref
  12. 12. A. V. Khvalkovskiy, D. Apalkov, S. Watts, R. Chepulskii, R. S. Beach, A. Ong, X. Tang, A. Driskill-Smith, W. H. Butler, P. B. Visscher, D. Lottis, E. Chen, V. Nikitin, and M. Krounbi, J. Phys. D: App. Phys. 46, 074001 (2013). https://doi.org/10.1088/0022-3727/46/7/074001, Google ScholarCrossref
  13. 13. A. D. Kent and D. C. Worledge, Nat. Nanotechnol. 10, 187 (2015). https://doi.org/10.1038/nnano.2015.24, Google ScholarCrossref
  14. 14. S. Manipatruni, D. E. Nikonov, and I. A. Young, Appl. Phys. Express 7, 103001 (2014). https://doi.org/10.7567/APEX.7.103001, Google ScholarCrossref
  15. 15. Y. Kim, X. Fong, K.-W. Kwon, M.-C. Chen, and K. Roy, IEEE Trans. Electron Dev. 62, 561 (2015). https://doi.org/10.1109/TED.2014.2377721, Google ScholarCrossref
  16. 16. M. I. Dyakonov and V. I. Perel, Phys. Lett. A 35, 459 (1971). https://doi.org/10.1016/0375-9601(71)90196-4, Google ScholarCrossref
  17. 17. J. E. Hirsch, Phys. Rev. Lett. 83, 1834 (1999). https://doi.org/10.1103/PhysRevLett.83.1834, Google ScholarCrossref
  18. 18. A. Hoffmann, IEEE Trans. Magn. 49, 5172 (2013). https://doi.org/10.1109/TMAG.2013.2262947, Google ScholarCrossref
  19. 19. J. Sinova, S. O. Valenzuela, J. Wunderlich, C. H. Back, and T. Jungwirth, Rev. Mod. Phys. 87, 1213 (2015). https://doi.org/10.1103/RevModPhys.87.1213, Google ScholarCrossref
  20. 20. Y. Seo, X. Fong, K.-W. Kwon, and K. Roy, IEEE Magn. Lett. 6, 3000204 (2015). https://doi.org/10.1109/LMAG.2015.2422260, Google ScholarCrossref
  21. 21. F. Oboril, R. Bishnoi, M. Ebrahimi, and M. B. Tahoori, IEEE Trans. Comput.-Aided Des. Integr. Circuits Syst. 34, 367 (2015). https://doi.org/10.1109/TCAD.2015.2391254, Google ScholarCrossref
  22. 22. L. Liu, T. Moriyama, D. C. Ralph, and R. A. Buhrman, Phys. Rev. Lett. 106, 036601 (2011). https://doi.org/10.1103/PhysRevLett.106.036601, Google ScholarCrossref
  23. 23. M. Hayashi, J. Kim, M. Yamanouchi, and H. Ohno, Phys. Rev. B 89, 144425 (2014). https://doi.org/10.1103/PhysRevB.89.144425, Google ScholarCrossref
  24. 24. S. Woo, M. Mann, A. J. Tan, L. Caretta, and G. S. D. Beach, Appl. Phys. Lett. 105, 212404 (2014). https://doi.org/10.1063/1.4902529, Google ScholarScitation, ISI
  25. 25. K. Garello, C. O. Avci, I. M. Miron, M. Baumgartner, A. Ghosh, S. Auffret, O. Boulle, G. Gaudin, and P. Gambardella, Appl. Phys. Lett. 105, 212402 (2014). https://doi.org/10.1063/1.4902443, Google ScholarScitation, ISI
  26. 26. C. Zhang, S. Fukami, H. Sato, F. Matsukura, and H. Ohno, Appl. Phys. Lett. 107, 012401 (2015). https://doi.org/10.1063/1.4926371, Google ScholarScitation, ISI
  27. 27. C.-F. Pai, L. Liu, Y. Li, H. W. Tseng, D. C. Ralph, and R. A. Buhrman, Appl. Phys. Lett. 101, 122404 (2012). https://doi.org/10.1063/1.4753947, Google ScholarScitation, ISI
  28. 28. M.-H. Nguyen, C.-F. Pai, K. X. Nguyen, D. A. Muller, D. C. Ralph, and R. A. Buhrman, Appl. Phys. Lett. 106, 222402 (2015). https://doi.org/10.1063/1.4922084, Google ScholarScitation, ISI
  29. 29. R. H. Koch, J. A. Katine, and J. Z. Sun, Phys. Rev. Lett. 92, 088302 (2004). https://doi.org/10.1103/PhysRevLett.92.088302, Google ScholarCrossref
  30. 30. Z. Li and S. Zhang, Phys. Rev. B 69, 134416 (2004). https://doi.org/10.1103/PhysRevB.69.134416, Google ScholarCrossref
  31. 31. H. Sato, M. Yamanouchi, S. Ikeda, S. Fukami, F. Matsukura, and H. Ohno, Appl. Phys. Lett. 101, 022414 (2012). https://doi.org/10.1063/1.4736727, Google ScholarScitation, ISI
  32. 32. P. M. Haney, H.-W. Lee, K.-J. Lee, A. Manchon, and M. D. Stiles, Phys. Rev. B 87, 174411 (2013). https://doi.org/10.1103/PhysRevB.87.174411, Google ScholarCrossref
  33. 33. M.-H. Nguyen, D. C. Ralph, and R. A. Buhrman, Phys. Rev. Lett. 116, 126601 (2016). https://doi.org/10.1103/PhysRevLett.116.126601, Google ScholarCrossref
  34. 34. C.-F. Pai, Y. Ou, L. H. Vilela-Leão, D. C. Ralph, and R. A. Buhrman, Phys. Rev. B 92, 064426 (2015). https://doi.org/10.1103/PhysRevB.92.064426, Google ScholarCrossref
  35. 35. W. Zhang, W. Han, X. Jiang, S.-H. Yang, and S. S. P. Parkin, Nat. Phys. 11, 496 (2015). https://doi.org/10.1038/nphys3304, Google ScholarCrossref
  36. 36. M.-H. Nguyen, M. Zhao, D. C. Ralph, and R. A. Buhrman, Appl. Phys. Lett. 108, 242407 (2016). https://doi.org/10.1063/1.4953768, Google ScholarScitation, ISI
  37. 37. Strictly speaking, these assumptions are valid only if proportionality constants between spin and momentum relaxation times are same for the bulk and the surface scattering. Google Scholar
  38. 38. R. J. Elliott, Phys. Rev. 96, 266 (1954). https://doi.org/10.1103/PhysRev.96.266, Google ScholarCrossref
  39. 39. Y. Yafet, Solid State Phys. 14, 1 (1963). https://doi.org/10.1016/S0081-1947(08)60259-3, Google ScholarCrossref
  40. 40. G. Y. Guo, S. Murakami, T. W. Chen, and N. Nagaosa, Phys. Rev. Lett. 100, 096401 (2008). https://doi.org/10.1103/PhysRevLett.100.096401, Google ScholarCrossref
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