Compositionally controlled FePt nanoparticle materials

Author

Sun, Shouheng ; Fullerton, Eric E. ; Weller, Dieter ; Murray, C.B.

Author_Institution

IBM Thomas J. Watson Res. Center, Yorktown Heights, NY, USA

Volume

37

Issue

4

fYear

2001

fDate

7/1/2001 12:00:00 AM

Firstpage

1239

Lastpage

1243

Abstract

High temperature solution phase decomposition of Fe(CO)₅ and reduction of Pt(acac)₂ in the presence of stabilizers, oleic acid and oleyl amine, are employed to produce 4 nm diameter FePt nanoparticles. The Fe and Pt composition of the nanoparticle materials can be tuned by adjusting the molar ratio of Fe(CO)₅ to Pt(acac)₂, and the compositions ranging from Fe₃₀Pt₇₀ to Fe₈₀Pt₂₀ are obtained. The nanoparticle materials are easily dispersed into alkane solvent, facilitating their self-organization into nanoparticle superlattices. As synthesized FePt nanoparticles possess a disordered fcc structure and show superparamagnetic behavior. Thermal annealing induces a change of internal particle structure and thus of the magnetic properties of the particles. Composition dependent structure analysis shows that an annealed FePt nanoparticle assembly with a composition around Fe₅₅Pt₄₅ will lead to the highly ordered fct phase. This Fe₅₅Pt₄₅ nanoparticle assembly yields high coercivity, and will be a candidate for future ultra-high density magnetic recording media applications

Keywords

annealing; coercive force; ferromagnetic materials; iron alloys; magnetic hysteresis; magnetic particles; magnetic recording; nanostructured materials; platinum alloys; self-assembly; superparamagnetism; 4 nm; Fe₃₀Pt₇₀; Fe₅₅Pt₄₅; Fe₈₀Pt₂₀; FePt; alkane solvent; coercivity; compositionally controlled FePt nanoparticle materials; disordered fcc structure; high temperature solution phase decomposition; highly ordered fct phase; internal particle structure; magnetic properties; molar ratio; nanoparticle superlattices; oleic acid; oleyl amine; reduction; self-organization; superparamagnetic behavior; thermal annealing; ultra-high density magnetic recording media; Annealing; Assembly; Composite materials; Iron; Magnetic materials; Magnetic superlattices; Nanoparticles; Nanostructured materials; Solvents; Temperature;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.950807

Filename

950807