Hostname: page-component-78c5997874-s2hrs Total loading time: 0 Render date: 2024-11-05T06:04:08.314Z Has data issue: false hasContentIssue false
  • English
  • Français

Factors Affecting Exchange Bias in Polycrystalline Metallic Thin Films

Published online by Cambridge University Press:  26 February 2011

Luis Eugenio Fernandez-Outon ,
Gonzalo Vallejo-Fernandez  and
Kevin O'Grady
Luis Eugenio Fernandez-Outon
Affiliation:
[email protected], The University of York, Department of Physics, Heslington, York, YO10 5DD, United Kingdom
Gonzalo Vallejo-Fernandez
Affiliation:
[email protected], The University of York, Department of Physics, Heslington, York, YO10 5DD, United Kingdom
Kevin O'Grady
Affiliation:
[email protected], The University of York, Department of Physics, Heslington, York, YO10 5DD, United Kingdom
Get access

Abstract

We describe the factors which control the measured value of exchange bias (HEX) in bilayers consisting of sputtered metallic thin films of an antiferromagnet (AF) in contact with a ferromagnetic (F) layer. Experimental measurements show that the value of HEX is determined by the grain volume distribution which limits the exchange bias via small grains which are thermally unstable, and large grains which cannot be set when the system is field annealed to set the AF at temperatures below TN. All the results are interpreted in terms of a granular model where the energy barrier to reversal within the AF is grain volume dependent. We show how this affects setting in metallic AFs at T<TN. We have also found that exchange bias is moderated by disordered spins at the F/AF interface. These spins can be ordered at low temperatures and by field annealing. Ordering of interfacial spins leads to an increase in HEX of up to 30%.

Keywords

polycrystalgrain sizethin film
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1032: Symposium I – Nanoscale Magnetic Materials and Applications , 2007 , 1032-I03-03
Copyright
Copyright © Materials Research Society 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Meiklejohn, W.H. and Bean, C.P., Phys.Rev. 102, 1413 (1956).10.1103/PhysRev.102.1413Google Scholar
2. Néel, L., Ann. Phys. (Paris) 2, 61 (1967).Google Scholar
3. Mauri, D., Kay, E., Scholl, D., and Howard, J. K., J. Appl. Phys. 62, 2929 (1987).10.1063/1.339374Google Scholar
4. Malozemoff, A. P., Phys. Rev. B 35, 3679 (1987).10.1103/PhysRevB.35.3679Google Scholar
5. Fulcomer, E., and Charap, S. H., J. Appl. Phys. 43, 4184 (1972).10.1063/1.1660893Google Scholar
6. Baibich, M., Broto, J., Fert, F., Dau, Nguyen Van, Petroff, F., Etienne, P., Creuzet, G., Friederich, A., and Chazelas, J., Phys. Rev. Lett. 61, 2472 (1988).10.1103/PhysRevLett.61.2472Google Scholar
7. Binasch, G., Grünberg, P., Saurenbach, F., and Zinn, W., Phys. Rev. B 39, 4828 (1989).Google Scholar
8. Moodera, J. S., Kinder, L. R., Wong, T. M., and Meservey, R., Phys. Rev. Lett. 74, 3273 (1995).Google Scholar
9. Jung, H. S., and Doyle, W. D., IEEE Trans. Magn. 39, 2291 (2003).10.1109/TMAG.2003.816275Google Scholar
10. Pakala, M., Huai, Y., and Anderson, G., IEEE Trans. Magn. 36, 2620 (2000).10.1109/20.908535Google Scholar
11. Fernandez-Outon, L. E., O'Grady, K., and Carey, M. J., J. Appl. Phys. 95, 6852 (2004).Google Scholar
12. Goodman, A. M., O'Grady, K., Laidler, H., Owen, N., Portier, X., Petford-Long, A. K., and Cebollada, F., IEEE Trans. Magn. 37, 565 (2001).10.1109/20.914379Google Scholar
13. Stamps, R. L., J. Phys. D: Appl. Phys. 33, R247 (2000), U. Nowak, K. D. Usadel, J. Keller, P. Miltényi, B. Beschoten, and G. Guntherodt, Phys. Rev. B 66, 014430 (2002).10.1088/0022-3727/33/23/201Google Scholar
14. Fulcomer, E., and Charap, S. H., J. Appl. Phys. 43, 4190 (1972).10.1063/1.1660894Google Scholar
15. Stoner, E.C., Wohlfarth, E.P., Philos. Trans. R. Soc. London Ser. A240, 599 (1948).10.1098/rsta.1948.0007Google Scholar
16. Baltz, V., Sort, J., Rodmacq, B., Dieny, B., and Landis, S., Phys. Rev. B 72, 104419 (2005).10.1103/PhysRevB.72.104419Google Scholar
17. Néel, L., Comp. Ann. Phys. (Paris) 5, 99 (1949).Google Scholar
18. Street, R., and Woolley, J. C., Proc. Phys. Soc. A62, 562 (1949).10.1088/0370-1298/62/9/303Google Scholar
19. Gaunt, P., J. Appl. Phys. 59, 4129 (1986).10.1063/1.336671Google Scholar
20. El-Hilo, M., O'Grady, K., and Chantrell, R. W., J. Magn. Magn. Mat. 109, L164 (1992).Google Scholar
21. Stiles, M. D., McMichael, R. D., Phys. Rev. B 59, 3722 (1999).10.1103/PhysRevB.59.3722Google Scholar
22.Some samples were provided by Hitachi Global Technology (San Jose) and Seagate Technology (Northern Ireland).Google Scholar
23. Vopsaroiu, M., Thwaites, M., Rand, S., Grundy, P. J. and O'Grady, K., IEEE Trans. Magn. 40, 2443 (2004).10.1109/TMAG.2004.828971Google Scholar
24. Stiles, M. D., McMichael, R. D., Phys. Rev. B 60, 12950 (1999).10.1103/PhysRevB.60.12950Google Scholar
25. Mauri, D., Siegmann, H. C., Bagus, P. S., and Kay, E., J. Appl. Phys. 62, 3047 (1987).10.1063/1.339367Google Scholar
26. Vallejo-Fernandez, G., Fernandez-Outon, L. E., and O'Grady, K., Appl. Phys. Lett. 91, 212503 (2007).10.1063/1.2817230Google Scholar
27. Carey, M. J., Smith, N., Gurney, B. A., Childress, J. R., and Lin, T., J. Appl. Phys. 89, 6579 (2001).10.1063/1.1358821Google Scholar
28. Dutson, J. D., Huerrich, C., Vallejo-Fernandez, G., Fernandez-Outon, L. E., Yi, G., Mao, S., Chantrell, R. W., and O'Grady, K., J. Phys. D: Appl. Phys. 40, 1293 (2007).10.1088/0022-3727/40/5/S16Google Scholar
29. Fernandez-Outon, L. E., Vallejo-Fernandez, G., and O'Grady, K., J. Appl. Phys. In Press(2008).Google Scholar