Current-induced magnetization dynamics in current perpendicular to the plane spin valves

Physical Review B - Condensed Matter and Materials Physics

Volumn 69, Issue 18, 2004, Pages

  Covington, M ^a   AlHajDarwish, M ^a,b   Ding, Y ^a,c   Gokemeijer, N J ^a   Seigler, M A ^a  

^a SEAGATE RESEARCH   (United States)

^b MICHIGAN STATE UNIVERSITY   (United States)

^c University of Minnesota   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

COBALT; COPPER; FERROMAGNETIC MATERIAL; IRIDIUM; IRON; MANGANESE; METAL COMPLEX; RUTHENIUM;

ARTICLE; DYNAMICS; ELECTRIC CURRENT; ELECTRIC RESISTANCE; MAGNETIC FIELD; MEASUREMENT; NOISE;

EID: 37649030087     PISSN: 01631829     EISSN: None     Source Type: Journal    
DOI: 10.1103/PhysRevB.69.184406     Document Type: Article

References (37)

1. J. C. Slonczewski, J. Magn. Magn. Mater. 159, L1 (1996).
2. L. Berger, Phys. Rev. B 54, 9353 (1996).
3. X. Waintal, E. B. Myers, P. W. Brouwer, and D. C. Ralph, Phys. Rev. B 62, 12317 (2000).
4. S. Zhang, P. M. Levy, and A. Fert, Phys. Rev. Lett. 88, 236601 (2002).
5. M. D. Stiles and A. Zangwill, J. Appl. Phys. 91, 6812 (2002).
6. K. Xia, P. J. Kelly, G. E. W. Bauer, A. Brataas, and I. Turek, Phys. Rev. B 65, 220401(R) (2002).
7. Ya. B. Bazaliy, B. A. Jones, and S.-C. Zhang, Phys. Rev. B 57, R3213 (1998).
8. Z. Li and S. Zhang, Phys. Rev. B 68, 024404 (2003).
9. J.-G. Zhu and X. Zhu, in Proceedings of The Magnetic Recording Conference (TMRC) 2003, Minneapolis, MN, 2003.
10. J. A. Katine, F. J. Albert, R. A. Buhrman, E. B. Myers, and D. C. Ralph, Phys. Rev. Lett. 84, 3149 (2000).
11. J. Grollier, V. Cros, A. Hamzic, J. M. George, H. Jaffrès, A. Fert, G. Faini, J. Ben Youssef, and H. Legall, Appl. Phys. Lett. 78, 3663 (2001).
12. J.-E. Wegrowe, A. Fábián, P. Guittienne, X. Hoffer, D. Kelly, J.-P. Ansermet, and E. Olive, Appl. Phys. Lett. 80, 3775 (2002).
13. J. Z. Sun, D. J. Monsma, D. W. Abraham, M. J. Rooks, and R. H. Koch, Appl. Phys. Lett. 81, 2202 (2002).
14. S. Urazhdin, N. O. Birge, W. P. Pratt, Jr., and J. Bass, Phys. Rev. Lett. 91, 146803 (2003).
15. M. Tsoi, A. G. M. Jansen, J. Bass, W.-C. Chiang, M. Seck, V. Tsoi, and P. Wyder, Phys. Rev. Lett. 80, 4281 (1998).
16. Y. Ji, C. L. Chien, and M. D. Stiles, Phys. Rev. Lett. 90, 106601 (2003).
17. W. H. Rippard, M. R. Pufall, and T. J. Silva, Appl. Phys. Lett. 82, 1260 (2003).
18. S. I. Kiselev, J. C. Sankey, I. N. Krivorotov, N. C. Emley, R. J. Schoelkopf, R. A. Buhrman, and D. C. Ralph, Nature (London) 425, 380 (2003).
19. W. H. Rippard, M. R. Pufall, S. Kaka, S. E. Russek, and T. J. Silva, Phys. Rev. Lett. 92, 027201 (2004).
20. J. Bass and W. P. Pratt, Jr., J. Magn. Magn. Mater. 200, 274 (1999).
21. B. Heinrich, Y. Tserkovnyak, G. Woltersdorf, A. Brataas, R. Urban, and G. E. W. Bauer, Phys. Rev. Lett. 90, 187601 (2003).
22. N. Smith and P. Arnett, Appl. Phys. Lett. 78, 1448 (2001).
23. V. L. Safonov and H. N. Bertram, Phys. Rev. B 65, 172417 (2002).
24. N. Stutzke, S. L. Burkett, and S. E. Russek, Appl. Phys. Lett. 82, 91 (2003).
25. See the reviews by P. Grünberg and H. A. M. van den Berg, in Magnetic Multilayers and Giant Magnetoresistance: Fundamentals and Industrial Applications, edited by U. Hartmann (Springer-Verlag, Berlin, 1999).
26. The small amplitude oscillations in the noise spectra are standing wave resonances originating from impedance discontinuities in the measurement system. The discontinuities are predominantly in the connectors, cables, and bias tees between the preamp and device, as verified by the observation that the oscillation period varies inversely with the length of coaxial cable between the device and preamp. The standing wave oscillations have only slightly larger amplitude when measuring a low resistance (total dc R ∼ 10 Ω) CPP device as opposed to a 50 Ω termination.
27. K. Eid, R. Fonck, M. AlHaj Darwish, W. P. Pratt, Jr., and J. Bass, J. Appl. Phys. 91, 8102 (2002).
28. The spectra were acquired from an unshielded device that coupled external narrow band noise into the measured spectra. These noise spikes appeared at frequencies below 2.5 GHz and have been omitted from the spectra. Similar noise measurements on devices inside a shielded box indicate that the external narrow band noise has no impact on the spectral features presented in this article.
29. The coherence times of the precessional state giving rise to the pronounced peak are currently unknown. Nevertheless, we refer to the entire spectrum as noise even though the dynamics may not be entirely random.
30. P. Dutta and P. M. Horn, Rev. Mod. Phys. 53, 497 (1981).
31. N. J. Gokemeijer, Y. Zhou, M. AlHajDarwish, Y. Ding, and M. A. Seigler, to be published.
32. We cite the AR value for the case of no hard axis field bias, as opposed to the value measured with a 1375 Oe hard axis field, since this represents the maximum AR measured for this particular bias current.
33. M. L. Polianski and P. W. Brouwer, Phys. Rev. Lett. 92, 026602 (2004).
34. M. D. Stiles, J. Xiao, and A. Zangwill, Phys. Rev. B 69, 054408 (2004).
35. W. H. Press, B. P. Flannery, S. A. Teukolsky, and W. T. Vetterling, Numerical Recipes (Cambridge U.P., Cambridge, 1989).
36. The noise spectrum at this bias point is very close to the one measured at 34 Oe shown in Fig. 2. The peak is essentially absent and the spectrum is dominated by 1/f noise.
37. RMS will only slightly change if the noise is integrated over a few more decades of frequency beyond the example discussed in the text.