Controlled Synthesis and Assembly of FePt Nanoparticles

Technical Report · Fri Jun 20 04:00:00 EDT 2003

DOI:https://doi.org/10.2172/813357· OSTI ID:813357

Toney, Michael F ^[1]

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1. SLAC

Monodisperse 4 nm FePt magnetic nanoparticles were synthesized by superhydride reduction of FeCl{sub 2} and Pt(acac){sub 2} at high temperature, and thin assemblies of FePt nanoparticles with controlled thickness were formed through polymer mediated self-assembly. Adding superhydride (LiBEt{sub 3}H) to the organic solution of FeCl{sub 2} and Pt(acac){sub 2} in the presence of oleic acid, oleylamine and 1,2-hexadecanediol at 200 C, followed by refluxing at 263 C led to monodisperse 4 nm FePt nanoparticles. The initial molar ratio of the metal precursors was retained during the synthesis; and the final FePt composition of the particles was readily tuned. Alternatively absorbing a layer of polyethylenimine (PEI) and the FePt nanoparticles onto a solid substrate resulted in nanoparticle assemblies with tunable thickness. Chemical analysis of the assemblies revealed that more iron oxide was present in the thinner assemblies annealed at lower temperature or for shorter time. Thermal annealing induced the internal particle structure change from chemically disordered fee to chemically ordered fct and transformed the thin assembly from superparamagnetic to ferromagnetic. This controlled synthesis and assembly can be used to fabricate FePt nanoparticle-based functional devices for future nanomagnetic applications.

• Research Organization: Stanford Linear Accelerator Center, Menlo Park, CA (US)
• Sponsoring Organization: USDOE Office of Science (US)
• DOE Contract Number: AC03-76SF00515
• OSTI ID: 813357
• Report Number(s): SLAC-PUB-9993
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANNEALING
CHARGES
CHEMICAL ANALYSIS
FUNCTIONALS
IRON OXIDES
OLEIC ACID
PARTICLE STRUCTURE
POLYMERS
SUBSTRATES
SYNTHESIS
THICKNESS