Surface spin disorder in ferrite nanoparticles (invited)

Journal of Applied Physics

Volumn 81, Issue 8 PART 2B, 1997, Pages 5552-5557

  Kodama, R H ^a   Berkowitz, A E ^a   McNiff Jr , E J ^b   Foner, S ^b  

^a UNIVERSITY OF CALIFORNIA   (United States)

^b MASSACHUSETTS INSTITUTE OF TECHNOLOGY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0347839632     PISSN: 00218979     EISSN: None     Source Type: Journal    
DOI: 10.1063/1.364659     Document Type: Article

References (22)

1. P. Vincent, J. Hammann, P. Prené, and E. Tronc, J. Phys. (France) 14, 273 (1994).
2. S. Mérup and E. Tronc. Phys. Rev. Lett. 70, 3278 (1994).
3. D. P. E. Dickson, N. M. K. Reid, C. Hunt, H. D. Williams, M. El-Hilo, and K. O'Grady, J. Magn. Magn. Mater. 125, 345 (1993).
4. D. D. Awschalom, J. F. Smyth, G. Grinstein, D. P. DiVincenzo, and D. Loss, Phys. Rev. Lett. 68, 3092 (1992).
5. A. E. Berkowitz, J. A. Lahut, I. S. Jacobs, L. M. Levinson, and D. W. Forester, Phys. Rev. Lett. 34, 594 (1975).
6. A. E. Berkowitz, J. A. Lahut, and C. E. VanBuren, IEEE Trans. Magn. MAG-16, 184 (1980).
7. W. J. Schuele and V. D. Deetscreek, J. Appl. Phys. 32S, 235S (1961).
8. J. M. D. Coey, Phys. Rev. Lett. 27, 1140 (1971).
9. A. H. Morrish and K. Haneda, J. Appl. Phys. 52, 2496 (1981).
10. Z. X. Tang, C. M. Sorensen, K. J. Klabunde, and G. C. Hadjipanayis, Phys. Rev. Lett. 67, 3602 (1991).
11. D. H. Han, J. P. Wang, and H. L. Luo, J. Magn. Magn. Mater. 136, 176 (1994).
12. D. Lin, A. C. Nunes, C. F. Majkrzak, and A. E. Berkowitz, J. Magn. Magn. Mater. 145, 343 (1995).
13. R. H. Kodama, A. E. Berkowitz, E. J. McNiff Jr., and S. Foner, Phys. Rev. Lett. 77, 394 (1996).
14. "Broken exchange bonds" are distinct from the idea of "spin pinning" proposed in the initial study (Ref. 5). Our recent measurements on a sample milled without surfactant show all the same anomalous effects, differing quantitatively by less than a factor of 2. In conjunction with the results of our calculation, this leads us to believe that chemical species other than surfactants can bind to surface ions and break exchang bonds. Surfactant removal by heating as performed in the initial study incurs the possibility of sintering and surface oxidation, which can act to decrease the sruface area and "heal" the broken bonds, thus reducing the surface spin disorder.
15. A. C. Nunes, E. L. Hall, and A. E. Berkowitz, J. Appl. Phys. 63, 5181 (1988).
16. R. H. Kodama, C. L. Seaman, A. E. Berkowitz, and M. B. Maple, J. Appl. Phys. 75, 5639 (1994).
17. E. M. Chudnovsky and L. Gunther, Phys. Rev. Lett. 60, 661 (1988).
18. B. Barbara et al., Studies of Magnetic Properties of Fine Particles, edited by J. L. Dormann and D. Fiorani (Elsevier Science, Amsterdam, Netherlands, 1992), p. 235.
19. A. A. Sidorov, V. P. Suetin, and V. G. Pokazan'ev, IAdernyi rezonans v tverdofaznykh soedineniiakh d-metallov, UNTs AN SSSR, Sverdlovsk (1984), pp. 21-31.
20. G. F. Hughes, J. Appl. Phys. 54, 5306 (1983).
21. A. K. Petrosyan and A. A. Mirzakhanyan, Phys. Status Solidi B 133, 315 (1986).
22. E. S. Kirkpatrick, K. A. Müller, and R. S. Rubins, Phys. Rev. 135, A86 (1964).