Abstract

We study magnetic hysteresis loops after field cooling of a CoO/Co bilayer by MOKE and polarized neutron reflectivity. The neutron scattering reveals that the first magnetization reversal after field cooling is dominated by domain wall movement, whereas all subsequent reversals proceed essentially by rotation of the magnetization. In addition, off-specular diffuse scattering indicates that the first magnetization reversal induces an irreversible change of the domain state in the antiferromagnet.

Author Keywords: Exchange bias; Magnetization reversal; Neutron reflectivity

Article Outline

References

(21K)
Fig. 1. (a) MOKE hysteresis loop of a CoO/Co bilayer after field cooling to 50 K in an external field of 2000 Oe. The black dots denote the first hysteresis loop, the open circles the second loop. Any further loops are not significantly different from the second. (b) and (c) Neutron hysteresis loops from the same sample but at 10 K. I++, I--, I+- and I-+ are non-spin flip and spin-flip intensities as a function of external magnetic field. They are measured at special scattering vector values of the reflectivity curves (see text); (d) Off-specular diffuse spin-flip scattering taken at H_c1=-750 Oe (full dots) and in saturation at -1400 Oe (open dots). (e) Specular spin-flip at H_c1 enlarged from panel (b) for better recognition.

References

1. W. Meiklejohn and C.P. Bean. Phys. Rev. 102 (1956), p. 1413. Full Text via CrossRef

2. W. Meiklejohn and C.P. Bean. Phys. Rev. 105 (1957), p. 904. Full Text via CrossRef

3. A.E. Berkowitz and K. Takano. JMM 200 (1999).

4. J. Nogues and I.K. Schuller. JMM 192 (1999).

5. M.R. Fitzsimmons, P. Yashar, C. Leighton, I.K. Schuller, J. Nogues, C.F. Majkrzak and J.A. Dura. Phys. Rev. Lett. 84 (2000), p. 3986. Abstract-INSPEC   | $Order Document | APS full text | Full Text via CrossRef

6. E. Fulcomer and S.H. Charap. J. Appl. Phys. 43 (1972), p. 4190. Abstract-INSPEC | Abstract-Compendex   | $Order Document

7. A.P. Malozemoff. Phys. Rev. B 35 (1987), p. 3679. Abstract-INSPEC   | $Order Document | Full Text via CrossRef

8. N.C. Koon. Phys. Rev. Lett. 78 (1997), p. 4865. Abstract-INSPEC   | $Order Document | APS full text | Full Text via CrossRef

9. M.D. Stiles and R.D. McMichael. Phys. Rev. B 59 (1999), p. 3722. Abstract-INSPEC   | $Order Document | APS full text | Full Text via CrossRef

10. P. Miltényi, M. Gierlings, J. Keller, B. Beschoten, G. Güntherodt, U. Nowak and K.D. Usadel. Phys. Rev. Lett. 84 (2000), p. 4224. Abstract-INSPEC   | $Order Document | APS full text | Full Text via CrossRef

11. R.L. Stamps. J. Phys. D 33 (2000).

12. F. Radu, M. Etzkorn, R. Siebrecht, V. Leiner, A. Schreyer, K. Westerholt, H. Zabel, in preparation.

13. F. Radu and V.K. Ignatovich. Physica B 267 (1999).

14. V.L. Aksenov, Yu.V. Nikitenko, F. Radu, Yu.M. Gledenov and P.V. Sedyshev. Physica B 276–278 (2000), p. 916.

15. S.G.E. te Velthuis, A. Berger, G.P. Felcher, B.K. Hill and E. Dan Dahlberg. J. Appl. Phys. 87 (2000), p. 5046. Abstract-INSPEC   | $Order Document | OJPS full text | Full Text via CrossRef

16. B.P. Toperverg. Physica B 297 (2001), p. 160. SummaryPlus | Full Text + Links | PDF (142 K)

17. H. Zabel, R. Siebrecht and A. Schreyer. Physica B 276–278 (2000), pp. 17–21. SummaryPlus | Full Text + Links | PDF (226 K)

Corresponding author. Fax: +49-234-3214-173; email: radu@spin.ep4.ruhr-uni-bochum.de