title: Morphology and magnetic flux distribution in superparamagnetic, single-crystalline Fe3O4nanoparticle rings.
abstract: This study reports on the correlation between crystal orientation and magnetic flux distribution of Fe3O4nanoparticles in the form of self-assembled rings. High-resolution transmission electron microscopy demonstrated that the nanoparticles were single-crystalline, highly monodispersed, (25 nm average diameter), and showed no appreciable lattice imperfections such as twins or stacking faults. Electron holography studies of these superparamagnetic nanoparticle rings indicated significant fluctuations in the magnetic flux lines, consistent with variations in the magnetocrystalline anisotropy of the nanoparticles. The observations provide useful information for a deeper understanding of the micromagnetics of ultrasmall nanoparticles, where the magnetic dipolar interaction competes with the magnetic anisotropy.
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , Sendai 980-8577, Japan.
authors.forename: Yumu
authors.initials: Y
authors.lastname: Takeno
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Murakami
authors.affiliation: Hitachi High-Technologies Corporation , 1040 Ichige, Hitachinaka-shi, Ibaraki 312-0033, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sato
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tanigaki
authors.forename: Hyun Soon
authors.initials: HS
authors.lastname: Park
authors.forename: Daisuke
authors.initials: D
authors.lastname: Shindo
authors.affiliation: LodeSpin Labs , P.O. Box 95632, Seattle, Washington 91845, USA.
authors.forename: R Matthew
authors.initials: RM
authors.lastname: Ferguson
authors.affiliation: Department of Materials Science and Engineering, University of Washington , Seattle, Washington 98195-2120, USA.
authors.forename: Kannan M
authors.identifier: 0000-0001-5010-7664
authors.initials: KM
authors.lastname: Krishnan