Optimized synthesis and magnetic properties of intermetallic Au 3Fe1-x, Au3Co1-x, and Au 3Ni1-x nanoparticles

James F. Bondi, Rajiv Misra, Xianglin Ke, Ian T. Sines, Peter Schiffer, Raymond E. Schaak

Research output: Contribution to journalArticlepeer-review

Abstract

Au and the 3d transition metals are immiscible under equilibrium conditions, but nonequilibrium alloys and intermetallic compounds of these elements are of interest for their potential multifunctional optical, catalytic, and magnetic properties. Here we report an optimized synthesis of intermetallic compounds with nominal compositions of Au3Fe1-x, Au 3Co1-x, and Au3Ni1-x as nanoparticles. Identification and optimization of the key synthetic variables (solvent, order of reagent addition, stabilizer, heating rate) led to the generation of nanoparticles with high phase purity and sample sizes of > 30 mg, which is an order of magnitude larger than what was previously achievable. These intermetallic nanoparticles, which have diffraction patterns consistent with the L12 structure type, were characterized by powder XRD, TEM, EDS, electron diffraction, UV-visible spectroscopy, and SQUID magnetometry. Aliquot studies showed that Au3Fe1-x formed through the initial nucleation of Au nanoparticles, followed by subsequent incorporation of Fe. Magnetic studies of powdered samples identified Au3Fe 1-x and Au3Co1-x as superparamagnetic with TB=7.9 and 2.4 K, respectively. Au3Ni1-x is paramagnetic down to 1.8 K.

Original languageEnglish (US)
Pages (from-to)3988-3994
Number of pages7
JournalChemistry of Materials
Volume22
Issue number13
DOIs
StatePublished - Jul 13 2010

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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