Magnetic nanoparticles with extremely high anisotropy such as chemically ordered L1o phase FePt nanoparticles have been considered one of the best candidates for future magnetic recording media with areal density beyond 1 Tbit/in2 for either the nanocomposite-film-type heat-assisted magnetic recording (HAMR) media or the self-organized-magnetic-array (SOMA)-type bit patterned media. However, current preparation methods via phase transformation must overcome many obstacles, including particle agglomeration, twinning, and difficulty of easy axis alignment. In this paper, the effort on and promise of the preparation of monodispersed magnetic nanoparticles with high anisotropy by a gas phase condensation method is reviewed and reported. The focus is to review recent progress on the fabrication of monodispersed highly ordered L10 phase FePt nanoparticles without phase transformation, successfully self-assembled and magnetically aligned magnetic nanoparticles for SOMA and HAMR media. The mechanisms for directly forming L1o phase FePt nanoparticles during nucleation and growth processes and magnetically aligning these particles are analyzed.
Bibliographical noteFunding Information:
Manuscript received September 17, 2007; revised June 16, 2008. Current version published December 2, 2008. This work was supported by the U.S. Department of Commerce, National Institute of Standards and Technology, Advanced Technology Program under Cooperative Agreement Number 70NANB1H3056 and in part by Seagate Technology and Heraeus Corp. The author is with the Center for Micromagnetic and Information Technology and the Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 USA (e-mail: firstname.lastname@example.org).
- Direct ordering
- Exchange coupled composite (ECC) media
- Graded media
- Heat-assisted magnetic recording (HAMR) media
- Heat-assisted recording media
- Magnetic nanoparticles
- Multilevel storage; nanocomposite
- Patterned media
- Self-organized magnetic array (SOMA)
- Shape-assisted assembly
- Tilted media