Magnetization directions of individual nanoparticles

Science

Volumn 284, Issue 5413, 1999, Pages 470-473

  Majetich, S A ^a   Jin, Y ^a  

^a CARNEGIE MELLON UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

IRON; NANOPARTICLE; OXIDE;

ANISOTROPY; ARTICLE; IMAGE ANALYSIS; MAGNETISM; MICROSCOPY; MODEL; PRIORITY JOURNAL;

EID: 0033574787     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.284.5413.470     Document Type: Article

References (37)

1. S. H. Charap, P. L. Lu. Y. He, IEEE Trans. Magn. 33, 978 (1997).
2. E. F. Kneller and F. E. Luborsky, J. Appl. Phys. 34, 656 (1963).
3. E. Kneller, in Magnetism and Metallurgy, A. Berkowitz and E. Kneller, Eds. (Academic Press, New York, 1969), p. 385.
4. B. D. Cullity, Introduction to Magnetic Materials (Addison-Wesley, Reading, MA, 1972), p. 301.
5. 50, the superparamagnetic limit, 34 nm, is predicted to be greater than the maximum monodomain size, 8.5 nm.
6. R. A. McCurrie and G. P. Carswell, J. Mater. Sci. 5, 825 (1970).
7. E. C. Stoner and E. P. Wohlfarth, Philos. Trans. R. Soc. London Ser. A 240, 599 (1948).
8. W. F. Brown Jr., J. Appl. Phys. 29, 470 (1958); K. D. Durst and H. Kronmüller, J. Magn. Magn. Mater. 68, 63 (1987).
9. W. F. Brown Jr., J. Appl. Phys. 29, 470 (1958); K. D. Durst and H. Kronmüller, J. Magn. Magn. Mater. 68, 63 (1987).
10. W. Wernsdorfer et al., Phys. Rev. Lett. 78, 1791 (1997).
11. A. D. Kent, T. M. Shaw, S. von Molnár, D. D. Awschalom, Science 262, 1249 (1993); J. Shi, S. Gider, K. Babcock, D. D. Awschatom, ibid. 271, 937 (1996).
12. A. D. Kent, T. M. Shaw, S. von Molnár, D. D. Awschalom, Science 262, 1249 (1993); J. Shi, S. Gider, K. Babcock, D. D. Awschatom, ibid. 271, 937 (1996).
13. S. Y. Chou, P. R. Krauss, L. Kong, J. Appl. Phys. 79, 6101 (1996).
14. J. Dooley and M. De Graef, Ultramicroscopy 67, 113 (1997); M. De Graef, N. T. Nuhfer, M. R. McCartney, J. Microsc., in press.
15. J. Dooley and M. De Graef, Ultramicroscopy 67, 113 (1997); M. De Graef, N. T. Nuhfer, M. R. McCartney, J. Microsc., in press.
16. H. W. Fuller and M. E. Hale, J. Microsc. 31, 238 (1960).
17. A. Hütten, J. Bernardi, C. Nelson, G. Thomas, Phys. Status Solidi A 150, 171 (1995).
18. C. Salling, S. Schultz, I. McFayden, M. Ozaki, IEEE Trans. Magn. 27, 5184 (1991); G. A. Gibson, J. F. Smyth, S. Schultz, D. P. Kern, ibid., p. 5187; M. Lederman, G. A. Gibson, S. Schultz, J. Appl. Phys. 73, 6961 (1993).
19. C. Salling, S. Schultz, I. McFayden, M. Ozaki, IEEE Trans. Magn. 27, 5184 (1991); G. A. Gibson, J. F. Smyth, S. Schultz, D. P. Kern, ibid., p. 5187; M. Lederman, G. A. Gibson, S. Schultz, J. Appl. Phys. 73, 6961 (1993).
20. C. Salling, S. Schultz, I. McFayden, M. Ozaki, IEEE Trans. Magn. 27, 5184 (1991); G. A. Gibson, J. F. Smyth, S. Schultz, D. P. Kern, ibid., p. 5187; M. Lederman, G. A. Gibson, S. Schultz, J. Appl. Phys. 73, 6961 (1993).
21. H. W. Fuller and M. E. Hale, J. Appl. Phys. 31, 1699 (1960).
22. S. A. Majetich and E. M. Kirkpatrick, IEEE Trans. Magn. 33, 3721 (1997); S. A. Majetich et al., Nanostruct. Mater. 9, 291 (1997).
23. S. A. Majetich and E. M. Kirkpatrick, IEEE Trans. Magn. 33, 3721 (1997); S. A. Majetich et al., Nanostruct. Mater. 9, 291 (1997).
24. 4 are expected to be superparamagnetic at room temperature. As found experimentally in J. Zhang, C. Boyd, and W. Luo [Phys. Rev. Lett. 77, 390 (1996)], when a ferrofluid is diluted so that the particle separation is large (as in the TEM samples we studied), Néel relaxation or superparamagnetic behavior is observed.
25. J. H. Scott and S. A. Majetich, Phys. Rev. B 52, 12564 (1995); Z. Turgut, J. H. Scott, M. Q. Huang, S. A. Majetich, M. E. McHenry, J. Appl. Phys. 83, 6468 (1998).
26. J. H. Scott and S. A. Majetich, Phys. Rev. B 52, 12564 (1995); Z. Turgut, J. H. Scott, M. Q. Huang, S. A. Majetich, M. E. McHenry, J. Appl. Phys. 83, 6468 (1998).
27. B. D. Cullity, Introduction to Magnetic Materials (Addison-Wesley, Reading, MA, 1972), p. 413.
28. M. Born and E. Wolf, Principles of Optics (Pergamon, Oxford, 1970), p. 420.
29. Y. Aharonov and D. Bohm, Phys. Rev. 115, 485 (1959).
30. D. Wohlleben, J. Appl. Phys. 38, 3341 (1967).
31. Z. L. Wang, Adv. Mater. 10, 13 (1998).
32. J. D. Jackson, Classical Electrodynamics (Wiley, New York, 1975), pp. 178 and 196-197.
33. R. A. McCurrie, Ferromagnetic Materials: Structure and Properties (Academic Press, New York, 1994), p. 142.
34. R. H. Kodama, A. E. Berkowitz, E. J. McNiff Jr., S. Foner, Phys. Rev. Lett. 77, 394 (1996).
35. C. W. Chen, Magnetism and Metallurgy of Soft Magnetic Materials (Dover, New York, 1986), p. 211.
36. F. Pfeifer and C. Radeloff, J. Magn. Magn. Mater. 19, 190 (1980).
37. We thank J. Suhan for microtomy sectioning and J. H. Scott for helpful discussions. SAM. thanks NSF for financial support (awards DMR-9285308 and DMR-9500313).