title: Monodisperse MFe2O4 (M = Fe, Co, Mn) nanoparticles.
abstract: High-temperature solution phase reaction of iron(III) acetylacetonate, Fe(acac)(3), with 1,2-hexadecanediol in the presence of oleic acid and oleylamine leads to monodisperse magnetite (Fe(3)O(4)) nanoparticles. Similarly, reaction of Fe(acac)(3) and Co(acac)(2) or Mn(acac)(2) with the same diol results in monodisperse CoFe(2)O(4) or MnFe(2)O(4) nanoparticles. Particle diameter can be tuned from 3 to 20 nm by varying reaction conditions or by seed-mediated growth. The as-synthesized iron oxide nanoparticles have a cubic spinel structure as characterized by HRTEM, SAED, and XRD. Further, Fe(3)O(4) can be oxidized to Fe(2)O(3), as evidenced by XRD, NEXAFS spectroscopy, and SQUID magnetometry. The hydrophobic nanoparticles can be transformed into hydrophilic ones by adding bipolar surfactants, and aqueous nanoparticle dispersion is readily made. These iron oxide nanoparticles and their dispersions in various media have great potential in magnetic nanodevice and biomagnetic applications.
authors.affiliation: IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA. ssun@us.ibm.com
authors.forename: Shouheng
authors.initials: S
authors.lastname: Sun
authors.forename: Hao
authors.initials: H
authors.lastname: Zeng
authors.forename: David B
authors.initials: DB
authors.lastname: Robinson
authors.forename: Simone
authors.initials: S
authors.lastname: Raoux
authors.forename: Philip M
authors.initials: PM
authors.lastname: Rice
authors.forename: Shan X
authors.initials: SX
authors.lastname: Wang
authors.forename: Guanxiong
authors.initials: G
authors.lastname: Li