Microstructural and magnetic characterization of alumina-iron nanocomposites
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Abstract
Iron-alumina nanocomposite powders containing 10 wt % iron were prepared by selective reduction of alumina-haematite solid solutions. Microstructural study showed three types of metal dispersion in the alumina matrix according to the elaboration process: iron grains that were >70 nm, most of the iron particles were <10 nm and directly epitaxied in the alumina matrix, and iron particles that were surrounded by an interfacial phase. In agreement with transmission electron miscroscopy (TEM) observations, magnetic study confirmed a distribution of the iron particles size, showing the superposition of a ferromagnetic behaviour (larger particles) and a superantiferromagnetic behaviour (smaller particles). Furthermore, analysis of thermoremanent behaviour, coercive field and dissymmetry of hysteresis loops allowed the interfacial phase surrounding some iron particles to be identified as an antiferromagnetic phase, Fe1+xAl2−xO4. Nevertheless, at the interface of metallic iron epitaxied on the alumina matrix some atomic planes always existed where iron was ionic (even if no other phase was detected). As a consequence the mean magnetic moment of iron in these nanocrystals is larger than that in bulk metallic iron.
Keywords
Iron Solid Solution Hysteresis Loop Alumina Matrix Coercive FieldPreview
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References
- 1.L. NÉEL, C.R. Hebd. Séanc. Acad. Sci. Paris 228 (1949) 664.Google Scholar
- 2.L. NÉEL, Ann. Geophys. 5 (1949) 99.Google Scholar
- 3.C. P. BEAN, J. Appl. Phys. 26 (1955) 1381.Google Scholar
- 4.C. KITTEL, Phys.Rev. 70 (1946) 965.Google Scholar
- 5.I. S. JACOBS and C. P. BEAN, in “Magnetism III”, edited by G. T. RADO and H. SUHL (Academic Press, New York, 1963) p. 271.Google Scholar
- 6.J. L. DORMANN, Revue Phys. Appl. 16 (1981) 275.Google Scholar
- 7.P. W. SELWOOD, “Adsorption and Collective Paramagnetism” (Academic Press, New York, 1962).Google Scholar
- 8.G. A. MARTIN, N. CEAPHALAU, P. De MONTGOLFIER and B. IMELIK, J. Chim. Phys. 70 (1973) 1422.Google Scholar
- 9.J. T. RICHARDSON, J. Appl. Phys. 49 (1978) 1781.Google Scholar
- 10.A. J. FREEMAN and C. L. FU, ibid. 61 (1987) 3356.Google Scholar
- 11.L. N. LIBERMANN, D. R. FREDKIN and H. B. SHORE, Phys. Rev. Lett. 22 (1969) 539.Google Scholar
- 12.L. N. LIBERMANN, J. CLINTON, P. M. EDARDS and J. MATHON, ibid. 25 (1970) 232.Google Scholar
- 13.S. OHNISHI, A. J. FREEMAN and M. WEINERT, Phys. Rev. B28 (1983) 6741.Google Scholar
- 14.G. M. PASTOR, J. DORANTE-DAVILA and K. M. BENNEMAN, ibid. B40 (1989) 7642.Google Scholar
- 15.S. MATSUO and I. J. NISHIDA, Phys. Soc. Jpn. 49 (1980) 1005.Google Scholar
- 16.A. ROUSSET and X. DEVAUX, French Patent 90 09790 (1990).Google Scholar
- 17.J. A. IMLACH and F. P. GLASSER, Trans. J. Brit. Ceram. Soc. 70 (1971) 227.Google Scholar
- 18.S. B. OGALE, D. M. PHASE, S. M. CHAUDARI, S. V. GHAISAS, S. M. KANETKAR, P. P. PATIL, V. G. BHIDE and S. K. DATE, Phys. Rev. B35 (1987) 1593.Google Scholar
- 19.R. ANTON, K. HEINEMANN and H. POPPA, Vide Couches Minces 201 (1980) 121.Google Scholar
- 20.S. B. QADRI, J. H. CLAASSEN, P. R. BROUSSARD and S. A. WOLF, J. Less-Common Metals 155 (1989) 327.Google Scholar
- 21.J. P. REBOUILLAT, Thése d'Etat, Université de Grenoble (1972).Google Scholar
- 22.J. H. M. STOELINGA, R. GERSDORF and G. De VRIES, Physica 41 (1969) 457.Google Scholar
- 23.S. FONER, A. J. FREEMAN, N. A. BLUM, R. B. FRANKEL, E. J. MCNIFF and H. C. PRADDANDE, Phys. Rev. 181 (1969) 863.Google Scholar
- 24.A. MARCHAND, X. DEVAUX, B. BARBARA, P. MOLLARD and A. ROUSSET, to be published.Google Scholar
- 25.B. BARBARA, J. FILIPPI, A. MARCHAND, P. MOLLARD, X. DEVAUX and A. ROUSSET, J. Phys., Paris 2 (1992) 101.Google Scholar
- 26.B. BARBARA, A. MARCHAND, P. MOLLARD, X. DEVAUX and A. ROUSSET, in International Workshop on Studies of Magnetic Properties of Fine Particles and Their Relevance to Materials Science, Rome, 4–8 November, 1991.Google Scholar
- 27.Idem, to be published.Google Scholar
- 28.L. NÉEL, Ann. Phys. 2 (1967) 61.Google Scholar
- 29.W. L. RUTH, J. Phys., Paris 25 (1964) 507.Google Scholar
- 30.S. J. PICKARD and A. C. TURNOCK, Phys. Chem. Solids 10 (1959) 242.Google Scholar
- 31.W. H. MEIKLEJOHN and C. P. BEAN, Phys. Rev. 102 (1956) 1413.Google Scholar
- 32.Idem, ibid. 105 (1957) 904.Google Scholar