title: Origin of surface canting within Fe3O4 nanoparticles.
abstract: The nature of near-surface spin canting within Fe3O4 nanoparticles is highly debated. Here we develop a neutron scattering asymmetry analysis which quantifies the canting angle to between 23° and 42° at 1.2 T. Simultaneously, an energy-balance model is presented which reproduces the experimentally observed evolution of shell thickness and canting angle between 10 and 300 K. The model is based on the concept of Td site reorientation and indicates that surface canting involves competition between magnetocrystalline, dipolar, exchange, and Zeeman energies.
authors.affiliation: NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Krycka
authors.affiliation: NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Borchers
authors.affiliation: Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Booth
authors.affiliation: Oberlin College, Oberlin, Ohio 44074, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Ijiri
authors.affiliation: Oberlin College, Oberlin, Ohio 44074, USA.
authors.forename: K
authors.initials: K
authors.lastname: Hasz
authors.affiliation: U.S. Department of Energy, Washington, D.C. 20585, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Rhyne
authors.affiliation: Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Majetich
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D052203:Ferrosoferric Oxide / Q000737:chemistry; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D060306:Magnetometry / Q000379:methods; D008956:Models, Chemical; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics
chemical_list: D001672:Biocompatible Materials; D058185:Magnetite Nanoparticles; D052203:Ferrosoferric Oxide