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Exchange Coupling and Spin-Flip Transition of CoFe2O4/α-Fe2O3 Bilayered Films

Published online by Cambridge University Press:  21 March 2011

Tatsuo Fujii
Affiliation:
Department of Applied Chemistry, Faculty of Engineering, Okayama University, Tsushima-naka 3-1-1, Okayama 700-8530, Japan
Takuya Yano
Affiliation:
Department of Applied Chemistry, Faculty of Engineering, Okayama University, Tsushima-naka 3-1-1, Okayama 700-8530, Japan
Makoto Nakanishi
Affiliation:
Department of Applied Chemistry, Faculty of Engineering, Okayama University, Tsushima-naka 3-1-1, Okayama 700-8530, Japan
Jun Takada
Affiliation:
Department of Applied Chemistry, Faculty of Engineering, Okayama University, Tsushima-naka 3-1-1, Okayama 700-8530, Japan
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Abstract

CoFe2O4/α-Fe2O3 (ferrimagnetic / antiferromagnetic) bilayered films were prepared on α-Al2O3(102) single-crystalline substrates by helicon plasma sputtering. A well-crystallized epitaxial α-Fe2O3(102) layer was formed on the substrate, while CoFe2O4 grown on α-Fe2O3(102) was a polycrystalline layer with a (100)-preferred orientation. The α-Fe2O3(102) films without CoFe2O4 layers clearly showed a spin-flip transition at about 400 K. The spins aligned perpendicular to the film plane at room temperature changed their direction within the film plane above 400 K. However the α-Fe2O3 base layers of CoFe2O4/α-Fe2O3 bilayered films did not show any spin-flip transition. The CoFe2O4 layer on α-Fe2O3 had a large in-plane magnetic anisotropy, while the spin axis of the α-Fe2O3(102) base layer was directed perpendicular to the film plane. The magnetization of ferrimagnetic CoFe2O4 layers was coupled perpendicularly to the spin axis of anitiferromagnetic α-Fe2O3 layers due to the exchange coupling at the interface between CoFe2O4 and α-Fe2O3.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

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References

REFERENCES

1. Koon, N. C., Phys. Rev. Lett., 78, 4865 (1997).Google Scholar
2. Hasegawa, N., Makino, A., Koike, F., Igarashi, K., IEEE. Trans, Magn., 32, 4618(1996).Google Scholar
3. Sakakima, H., Sugita, Y., Satomi, M., Kawawake, Y., J. Magn. Magn. Mat., 198–199, 9 (1999).Google Scholar
4. Fujii, T., Takano, M., Katano, R., Isozumi, Y., Bando, Y., J. Magn. Magn. Mat., 135, 231 (1994).Google Scholar
5. Zaag, P. J. van der, Ball, A. R., Feiner, L. F., and Wolf, R. M., Heijden, P. A. A. van der, J. Appl. Phys., 79, 5103 (1996).10.1063/1.361315Google Scholar
6. Fujii, T., Yano, T., Nakanishi, M., Takada, J., in Proceedings of the 8th International Conference on Ferrites (Kyoto, 2000) in press.Google Scholar
7. Wang, X., Matsumoto, H., Someno, Y., Hirai, T., Appl. Phys. Lett., 72, 3264 (1998).Google Scholar
8.JCPDS, Powder Diffraction File, 22-1086.Google Scholar
9. Smit, J., Wijn, H.P.J., Ferrites, Philips Technical Library, Eindhoven, the Netherlands, 1959, p.162.Google Scholar