title: Characterization of multifunctional β-NaEuF4/NaGdF4 core-shell nanoparticles with narrow size distribution.
abstract: The properties of β-NaEuF4/NaGdF4 core-shell nanocrystals have been thoroughly investigated. Nanoparticles with narrow size distribution and an overall diameter of ∼22 nm have been produced with either small β-NaEuF4 cores (∼3 nm diameter) or large β-NaEuF4 cores (∼18 nm diameter). The structural properties and core-shell formation are investigated by X-ray diffraction, transmission electron microscopy and electron paramagnetic resonance, respectively. Optical luminescence measurements and X-ray photoelectron spectroscopy are employed to gain information about the optical emission bands and valence states of the rare earth constituents. Magnetic characterization is performed by SQUID and X-ray magnetic circular dichroism measurements at the rare earth M(4,5) edges. The characterization of the core-shell nanoparticles by means of these complementary techniques demonstrates that partial intermixing of core and shell materials takes place, and a significant fraction of europium is present in the divalent state which has significant influence on the magnetic properties. Hence, we obtained a combination of red emitting Eu(3+) ions and paramagnetic Gd(3+) ions, which may be highly valuable for potential future applications.
authors.affiliation: Department of Physics, Center of Physics and Chemistry of New Materials, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany. lischroe@uos.de kkuepper@uos.de.
authors.forename: Lilli
authors.initials: L
authors.lastname: Schneider
authors.affiliation: Institute of Chemistry of New Materials, Center of Physics and Chemistry of New Materials, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany.
authors.forename: Thorben
authors.initials: T
authors.lastname: Rinkel
authors.affiliation: Institute of Chemistry of New Materials, Center of Physics and Chemistry of New Materials, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Voß
authors.affiliation: Institute of Physics, Silesian University, Uniwersytecka 4, 40-007 Katowice, Poland.
authors.forename: Artur
authors.initials: A
authors.lastname: Chrobak
authors.affiliation: Department of Physics, Center of Physics and Chemistry of New Materials, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany. lischroe@uos.de kkuepper@uos.de.
authors.forename: Johann P
authors.initials: JP
authors.lastname: Klare
authors.affiliation: Centre for HRTEM, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth, South Africa.
authors.forename: Jan
authors.initials: J
authors.lastname: Neethling
authors.affiliation: Centre for HRTEM, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth, South Africa.
authors.forename: Jaco
authors.initials: J
authors.lastname: Olivier
authors.affiliation: Université de Lorraine, CRM2, UMR 7036, Vandoeuvre-les-Nancy, F-54506, France.
authors.forename: Dominik
authors.initials: D
authors.lastname: Schaniel
authors.affiliation: Université de Lorraine, CRM2, UMR 7036, Vandoeuvre-les-Nancy, F-54506, France.
authors.forename: El-Eulmi
authors.initials: el-E
authors.lastname: Bendeif
authors.affiliation: IOM CNR, Laboratorio TASC, S.S. 14 km 163.5, 34149 Basovizza, Trieste, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Bondino
authors.affiliation: IOM CNR, Laboratorio TASC, S.S. 14 km 163.5, 34149 Basovizza, Trieste, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Magnano
authors.affiliation: IOM CNR, Laboratorio TASC, S.S. 14 km 163.5, 34149 Basovizza, Trieste, Italy and Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5, 34149 Basovizza, Trieste, Italy.
authors.forename: Igor
authors.initials: I
authors.lastname: Píš
authors.affiliation: Department of Physics, Center of Physics and Chemistry of New Materials, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany. lischroe@uos.de kkuepper@uos.de.
authors.forename: Kamil
authors.initials: K
authors.lastname: Balinski
authors.affiliation: Department of Physics, Center of Physics and Chemistry of New Materials, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany. lischroe@uos.de kkuepper@uos.de.
authors.forename: Joachim
authors.initials: J
authors.lastname: Wollschläger
authors.affiliation: Department of Physics, Center of Physics and Chemistry of New Materials, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany. lischroe@uos.de kkuepper@uos.de.
authors.forename: Heinz-Jürgen
authors.initials: HJ
authors.lastname: Steinhoff
authors.affiliation: Institute of Chemistry of New Materials, Center of Physics and Chemistry of New Materials, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Haase
authors.affiliation: Department of Physics, Center of Physics and Chemistry of New Materials, Universität Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany. lischroe@uos.de kkuepper@uos.de.
authors.forename: Karsten
authors.initials: K
authors.lastname: Kuepper