title: Direct investigation of superparamagnetism in Co nanoparticle films.
abstract: A direct probe of superparamagnetism was used to determine the complete anisotropy energy distribution of Co nanoparticle films. The films were composed of self-assembled lattices of uniform Co nanoparticles of 3 or 5 nm in diameter, and a variable temperature scanning-SQUID microscope was used to measure temperature-induced spontaneous magnetic noise in the samples. Accurate measurements of anisotropy energy distributions of small volume samples will be critical to magnetic optimization of nanoparticle devices and media.
authors.affiliation: IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA.
authors.forename: S I
authors.initials: SI
authors.lastname: Woods
authors.forename: J R
authors.initials: JR
authors.lastname: Kirtley
authors.forename: S
authors.initials: S
authors.lastname: Sun
authors.forename: R H
authors.initials: RH
authors.lastname: Koch