jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter UniPHY Group iResearch App Facebook

Journal of Applied Physics / Volume 100 / Issue 11 / NANOSCALE SCIENCE AND DESIGN

J. Appl. Phys. 100, 114324 (2006); http://dx.doi.org/10.1063/1.2399885 (7 pages)

Cobalt ferrite nanoparticles: Achieving the superparamagnetic limit by chemical reduction

P. Jeppson1, R. Sailer1, E. Jarabek1, J. Sandstrom1, B. Anderson1, M. Bremer1, D. G. Grier1, D. L. Schulz1, A. N. Caruso1, S. A. Payne2, P. Eames3, Mark Tondra3, Hongshan He4, and D. B. Chrisey5

1Center for Nanoscale Science and Engineering, North Dakota State University, Fargo, North Dakota 58102
2Electron Microscopy Center, North Dakota State University, Fargo, North Dakota 58105
3NVE Corporation, Eden Prairie, Minnesota 55344
4Department of Chemistry, North Dakota State University, Fargo, North Dakota 58105
5Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180

View MapView Map

(Received 19 July 2006; accepted 22 September 2006; published online 14 December 2006)

An unanticipated superparamagnetic response has been observed in cobalt ferrite materials after thermal treatment under inert atmosphere. Cobalt ferrite particles were prepared via normal micelle precipitation that typically yields CoxFe3−xO4 nanoparticles (x = 0.6−1.0). While samples thermally treated under oxygen show majority spinel phase formation, annealing in nitrogen gas yields materials consisting of Co-Fe alloy, FeS, and CoFe2O4 spinel. After thermal treatment, thermomagnetic studies reveal composition-insensitive, but highly treatment-sensitive, saturation magnetization, coercivity, blocking temperature, and Verwey transition temperature dependence. Extremely high saturation magnetization (159 emu/g) with low coercivity (31 Oe) was observed for one of the treated compositions, which drastically deviates from prototypical cobalt ferrite with large magnetocrystalline anisotropy. We attribute such unique magnetic response to Co-Fe alloy coexisting with FeS and CoFe2O4 spinel where the diameter of the metallic phase is below the superparamagnetic limit. While thermal treatment in nitrogen was not anticipated to yield Co-Fe alloy, chemisorbed surfactant molecules (i.e., sodium dodecylsulfate) are postulated to act as reducing agents in the present scenario.

© 2006 American Institute of Physics

Article Outline

  1. INTRODUCTION
  2. EXPERIMENT
  3. RESULTS
    1. X-ray diffraction analysis: Phase identification
    2. Magnetic measurements
    3. Particle diameter
  4. DISCUSSION
    1. Treatment and composition dependence on nanoparticle magnetic response
    2. Treatment implications on nanoparticle structure
    3. Temperature dependence of the magnetization
    4. Anisotropy and reduced remanence
  5. CONCLUSION

RELATED DATABASES

To view database links for this article, you need to log in.

KEYWORDS and PACS

Keywords

cobalt compounds, ferrites, nanoparticles, magnetic particles, superparamagnetism, reduction (chemical), annealing, precipitation, magnetocaloric effects, coercive force, metal-insulator transition, magnetic anisotropy

PACS

  • 75.20.-g

    Diamagnetism, paramagnetism, and superparamagnetism

  • 75.50.Tt

    Fine-particle systems; nanocrystalline materials

  • 75.50.Gg

    Ferrimagnetics

  • 82.30.-b

    Specific chemical reactions; reaction mechanisms

  • 81.40.Gh

    Other heat and thermomechanical treatments

  • 75.60.Ej

    Magnetization curves, hysteresis, Barkhausen and related effects

ARTICLE DATA

Digital Object Identifier
http://dx.doi.org/10.1063/1.2399885

PUBLICATION DATA

ISSN

0021-8979 (print)  
1089-7550 (online)

Publisher

$abstract.society.value is a Member of CrossRef American Institute of Physics

For access to fully linked references, you need to log in.
    G. F. Goya, T. S. Berquo, F. C. Fonseca, and M. P. Morales, J. Appl. Phys. 94, 3520 (2003)JAPIAU000094000005003520000001.

    Z. X. Tang, C. M. Sorensen, K. J. Klabunde, and G. C. Hadjipanayis, Phys. Rev. Lett. 67, 3602 (1991).

    G. U. Kulkarni, K. R. Kannan, T. Arunarkavalli, and C. N. R. Rao, Phys. Rev. B 49, 724 (1994).

    J. P. Chen, C. M. Sorensen, K. J. Klabunde, G. C. Hadjipanayis, E. Devlin, and A. Kostikas, Phys. Rev. B 54, 9288 (1996).

    A. M. Testa et al., J. Appl. Phys. 90, 1534 (2001)JAPIAU000090000003001534000001.

    H. H. Hamdeh, W. M. Hikal, S. M. Taher, J. C. Ho, N. P. Thuy, O. K. Quy, and N. Hanh, J. Appl. Phys. 97, 064310 (2005)JAPIAU000097000006064310000001.

    F. Bodker, S. Morup, and S. Linderoth, Phys. Rev. Lett. 72, 282 (1994).

    S. Li V. T. John, C. O'Conner, V. Harris, and E. Carpenter, J. Appl. Phys. 87, 6223 (2000)JAPIAU000087000009006223000001.

    A. K. Giri, E. M. Kirkpatrick, P. Moongkhamklang, S. A. Majetich, and V. G. Harris, Appl. Phys. Lett. 80, 2341 (2002)APPLAB000080000013002341000001.

    J. Dai, J. -Q. Wang, C. Sangregorio, J. Fang, E. Carpenter, and J. Tang, J. Appl. Phys. 87, 7397 (2000)JAPIAU000087000010007397000001.

    F. T. Parker, F. E. Spada, T. J. Cox, and A. E. Berkowitz, J. Appl. Phys. 77, 5853 (1995)JAPIAU000077000011005853000001.

    P. J. van der Zaag, J. J. M. Ruigrok, A. Noordermeer, M. H. W. M. van Delden, P. T. Por, M. Th. Rekveldt, D. M. Donnet, and J. N. Chapman, J. Appl. Phys. 74, 4085 (1993)JAPIAU000074000006004085000001.

    R. H. Kodama, A. E. Berkowitz, E. J. McNiff, and S. Foner, Phys. Rev. Lett. 77, 394 (1996).

    J. M. D. Coey, Phys. Rev. Lett. 27, 1140 (1971).

    J. C. Slonczewski, Phys. Rev. 110, 1341 (1958).

    T. Goto, Y. Shindo, H. Takahashi, and S. Ogawa, Phys. Rev. B 56, 14019 (1997).

    H. S. Jarrett, W. H. Cloud, R. J. Bouchard, S. R. Butler, C. G. Fredrick, and J. L. Gillson, Phys. Rev. Lett. 21, 617 (1968).

    I. I. Mazin, Appl. Phys. Lett. 77, 3000 (2000)APPLAB000077000019003000000001.

    G. L. Zhao, J. Callaway, and M. Hayashibara, Phys. Rev. B 48, 15781 (1993).

    S. K. Kwon, S. J. Youn, and B. I. Min, Phys. Rev. B 62, 357 (2000).

    K. Ramesha, R. Seshadri, C. Ederer, T. He, and M. A. Subramanian, Phys. Rev. B 70, 214409 (2004).

    I. F. Silvera, J. H. M. Thornley, and M. Tinkham, Phys. Rev. 136, A695 (1964).

    L. S. Birks and H. Friedman, J. Appl. Phys. 17, 687 (1946)JAPIAU000017000008000687000001.

    H. Shenker, Phys. Rev. 107, 1246 (1957).

    C. Rath, K. K. Sahu, S. D. Kulkarni, S. Anand, S. K. Date, R. P. Das, and N. C. Mishra, Appl. Phys. Lett. 75, 4171 (1999)APPLAB000075000026004171000001.


For access to citing articles, you need to log in.


Figures (6) Tables (2)

Access to article objects (figures, tables, multimedia) requires a subscription; log in to view available files.
(Access to supplementary files, where available, is free for this journal.)

Access to article objects (figures, tables, multimedia) requires a subscription; log in to view available files.
(Access to supplementary files, where available, is free for this journal.)



Close

Google Calendar

ADVERTISEMENT

Your Recent History Recent History Help

Recently Viewed

  1. Cobalt ferrite nanoparticles: Achieving the superparamagnetic limit by chemical reduction
  2. Analysis of 60 nm diam spin dependent tunneling memory cells with thermally assisted writing
  3. Strained Si, SiGe, and Ge channels for high-mobility metal-oxide-semiconductor field-effect transistors
  4. Micromechanics of actuation of ionic polymer-metal composites
  5. Prototype spin-dependent tunneling isolators integrated with integrated circuit electronics
Go to AIP Home
Copyright © American Institute of Physics
close