Direct synthesis and easy axis alignment of L1{sub 0}-FePt nanoparticles

Journal Article · Sun May 15 00:00:00 EDT 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1855203· OSTI ID:20711649

Shishou, Kang; Zhiyong, Jia; Shifan, Shi; Nikles, David E; Harrell, J W ^[1]

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1. Center for Materials for Information Technology, University of Alabama, Tuscaloosa, Alabama 35487-0209 (United States)

Partially ordered Fe{sub 53}Pt{sub 47} nanoparticles with size around 8 nm were prepared by the simultaneous decomposition of iron pentacarbonyl and platinum acetylacetonate. The high boiling point chemical, hexadecylamine, was used as a solvent, and 1-adamantanecarboxylic acid was used as a stabilizer. The reflux temperature of the solution could exceed 360 deg. C, where disordered FePt particles could be partially transformed into the ordered L1{sub 0} phase. A nonmagnetic mechanical stirrer was used in order to avoid agglomeration of the fct-FePt particles during synthesis. The particles were dispersed in toluene and films of the particles were cast onto silicon wafers from the solution. X-ray diffraction patterns of as-made samples showed weak superlattice peaks, indicating partial chemical ordering of the Fe{sub 53}Pt{sub 47} particles. The room-temperature hysteresis loop of the as-made sample reveals a small coercivity ({approx}600 Oe) because of thermal fluctuations; however, the loop is wide open and hard to saturate. The remanence coercivity from the dcd curve is about 2.5 kOe, which is four times larger than the hysteresis coercivity. The large remanent to hysteresis coercivity ratio and the shapes of the hysteresis loop and dcd curve suggest a broad distribution of anisotropies in the partially ordered particles. By coating the ordered nanoparticles with a polymer binder, the easy axis of the particles could be aligned under an external field.

• OSTI ID: 20711649
• Journal Information: Journal of Applied Physics, Vol. 97, Issue 10; Conference: 49. annual conference on magnetism and magnetic materials, Jacksonville, FL (United States), 7-11 Nov 2004; Other Information: DOI: 10.1063/1.1855203; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGGLOMERATION
ANISOTROPY
BOILING POINTS
COERCIVE FORCE
FERROMAGNETIC MATERIALS
FILMS
HYSTERESIS
IRON ALLOYS
NANOSTRUCTURES
ORDER-DISORDER TRANSFORMATIONS
PARTICLES
PLATINUM ALLOYS
POLYMERS
PYROLYSIS
SILICON
SOLUTIONS
SUPERLATTICES
TEMPERATURE RANGE 0273-0400 K
TOLUENE
X-RAY DIFFRACTION