title: Increased surface spin stability in γ-Fe2O3 nanoparticles with a Cu shell.
abstract: γ-Fe(2)O(3) nanoparticles  were coated with a Cu shell in situ during synthesis. An interfacial monolayer of CuO in the Cu-coated γ-Fe(2)O(3) nanoparticles was discovered that stabilized the disordered surface spins of γ-Fe(2)O(3) nanoparticles. Element-specific x-ray absorption spectroscopy at the L-edges for Cu and Fe indicated the magnetic moment of the Cu in the shell interacted with the γ-Fe(2)O(3) nanoparticle's surface magnetic moments. This exchange interaction between the Fe and Cu at the interface permitted an overall Cu moment in CuO (an antiferromagnet typically) that altered the γ-Fe(2)O(3) nanomagnetism. Increasing the Cu shell thickness also increased the total Fe magnetism of the nanoparticles.
authors.affiliation: Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
authors.forename: R D
authors.initials: RD
authors.lastname: Desautels
authors.forename: E
authors.initials: E
authors.lastname: Skoropata
authors.forename: Y-Y
authors.initials: YY
authors.lastname: Chen
authors.forename: H
authors.initials: H
authors.lastname: Ouyang
authors.forename: J W
authors.initials: JW
authors.lastname: Freeland
authors.forename: J
authors.initials: J
authors.lastname: van Lierop
mesh_terms: D003300:Copper / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D010316:Particle Size; D013499:Surface Properties; D056928:X-Ray Absorption Spectroscopy
chemical_list: D005290:Ferric Compounds; D003300:Copper; C030973:cupric oxide