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Microstructure and magnetic properties in percolating (Ni–Fe)x(SiO2)1–x granular films

Published online by Cambridge University Press:  31 January 2011

Y. Xu  and
X. Yan
Y. Xu
Affiliation:
Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
X. Yan
Affiliation:
Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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Abstract

We studied composition, structure, microstructure, and magnetic properties of percolating (Ni–Fe)x(SiO2)1−x granular thin films. We found that the magnetic susceptibility increases and the coercivity decreases when increasing x toward xt, the critical metallic volume fraction for the metal-insulator transition, and the susceptibility decreases and the coercivity increases when increasing annealing temperature for x just below xt. Comparison of the microstructure and the magnetic properties suggests that the enhanced magnetic susceptibility for x just below xt is probably associated with the labyrinthine structure of the granular magnetic particles where there is an enhanced surface-to-volume ratio of the magnetic particles.

Type
Articles
Information
Journal of Materials Research , Volume 11 , Issue 10 , October 1996 , pp. 2506 - 2517
Copyright
Copyright © Materials Research Society 1996

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References

REFERENCES

1. Gittleman, J. I., Goldstein, Y., and Bozowski, Phys. Rev. B 5, 3609 (1972);CrossRefGoogle Scholar
Abeles, B., Sheng, P., Couts, M. D., and Arie, Y., Adv. Phys. 24, 407 (1975);CrossRefGoogle Scholar
Abeles, B., Pinch, H. L., and Gittleman, J. I., Phys. Rev. Lett. 35, 247 (1975).CrossRefGoogle Scholar
2. Xiao, G. and Chien, C. L., Appl. Phys. Lett. 51, 1280 (1987);CrossRefGoogle Scholar
Gavrin, A. and Chien, C. L., J. Appl. Phys. 67, 938 (1990);CrossRefGoogle Scholar
Chien, C. L., J. Appl. Phys. 69, 5267 (1991).CrossRefGoogle Scholar
3. Carl, A., Dumpich, G., and Wassermann, E. F., Phys. Rev. B 50, 4802 (1994);CrossRefGoogle Scholar
Carl, A., Dumpich, G., and Wassermann, E. F., Phys. Rev. B 50, 7838 (1994).CrossRefGoogle Scholar
4. See articles in Physical Phenomena in Granular Materials, edited by Cody, G. D., Geballe, T. H., and Sheng, Ping (MRS, Pittsburgh, PA, 1990).Google Scholar
5. Schlesinger, T. E., Cammarata, R. C., Gavrin, A., Xiao, J.Q., Chien, C. L., Ferber, M. K., and Hayzelden, C., J. Appl. Phys. 70, 3275 (1991);CrossRefGoogle Scholar
Scanlon, M. R. and Cammarata, R. C., J. Appl. Phys. 76, 3387 (1994).CrossRefGoogle Scholar
6. Berkowitz, A. E., Mitchell, J. R., Carey, M. J., Young, A. P., Zhang, S., Spada, F. E., Parker, F. T., Hutten, A., and Thomas, G., Phys. Rev. Lett. 68, 3745 (1992);CrossRefGoogle Scholar
Xiao, J.Q., Jiang, J.S., and Chien, C. L., Phys. Rev. Lett. 68, 3749 (1992).CrossRefGoogle Scholar
7. Xiao, G., Wang, J.Q., and Xiong, P., Appl. Phys. Lett. 62, 420 (1993);CrossRefGoogle Scholar
Wang, J.Q. and Xiao, G., Phys. Rev. B 49, 3982 (1994).CrossRefGoogle Scholar
8. Pakhomov, A. B., Yan, X., and Zhao, B., Appl. Phys. Lett. 67 (23), 3497 (1995).CrossRefGoogle Scholar
9. (a) Pakhomov, A. B., Yan, X., and Xu, Y., J. Appl. Phys. 79, 6140 (1996);CrossRefGoogle Scholar
(b) Jing, X. N., Wang, N., Pakhomov, A. B., Fung, K. K., and Yan, X., Phys. Rev. B 53, 14 032 (1996).CrossRefGoogle Scholar
10. Xu, Y., Zhao, B., and Yan, X., J. Appl. Phys. 79, 6137 (1996).CrossRefGoogle Scholar
11. Lipson, H. and Steeple, H., Interpretation of X-ray Powder Diffraction Patterns (Macmillan, London, 1970).Google Scholar
12. The size determined by the x-ray appears to be consistently smaller than that determined by the TEM bright-field images. The reality is likely somewhere in between due to the difference in the nature of the techniques. The width of the x-ray diffraction peak is a good way to determine the crystal size when there is a fixed size with no lattice deformation and no strain. Error could arise otherwise, leading to an underestimation of the crystal size, and certainly the particle size since a particle may contain multigrains. While the TEM bright-field image is essentially a Fourier transform of the diffraction peaks, it is accurate for dilute case in determining the size of particles, but tends to overestimate the size when there is considerable overlap of different particles in space, particularly since the image was obtained via an average over the specimen thickness.Google Scholar
13. Zhao, B., Chow, J. Y., Yan, X., J. Appl. Phys. 79 6022 (1996).CrossRefGoogle Scholar
14. Herzer, G., IEEE Trans. Magn. MAG 25, 3327 (1989), and MAG 26, 1397 (1990).CrossRefGoogle Scholar
15. Chien, C. L., in Science and Technology of Nanostructured Magnetic Materials, edited by Hadjipanayis, G. C. and Prinz, G. A. (Plenum Press, New York, 1991), p. 477.CrossRefGoogle Scholar
16. Sheng, P., Abeles, B., and Arie, Y., Phys. Rev. Lett. 37, 1429 (1976).CrossRefGoogle Scholar
17. Hasegawa, N., Saito, M., Kataoka, N., and Fujimori, H., J. Mater. Eng. and Perform. 2, 181 (1993).CrossRefGoogle Scholar
18. Ohnuma, S., Fujimori, H., Mitani, S., and Masumoto, T., Proc. 40th Ann. Conf. on Magn. and Magn. Mater., Philadelphia, Nov. 6–9, 1995, to appear in J. Appl. Phys.Google Scholar