title: Structural and magnetic properties of multi-core nanoparticles analysed using a generalised numerical inversion method.
abstract: The structural and magnetic properties of magnetic multi-core particles were determined by numerical inversion of small angle scattering and isothermal magnetisation data. The investigated particles consist of iron oxide nanoparticle cores (9 nm) embedded in poly(styrene) spheres (160 nm). A thorough physical characterisation of the particles included transmission electron microscopy, X-ray diffraction and asymmetrical flow field-flow fractionation. Their structure was ultimately disclosed by an indirect Fourier transform of static light scattering, small angle X-ray scattering and small angle neutron scattering data of the colloidal dispersion. The extracted pair distance distribution functions clearly indicated that the cores were mostly accumulated in the outer surface layers of the poly(styrene) spheres. To investigate the magnetic properties, the isothermal magnetisation curves of the multi-core particles (immobilised and dispersed in water) were analysed. The study stands out by applying the same numerical approach to extract the apparent moment distributions of the particles as for the indirect Fourier transform. It could be shown that the main peak of the apparent moment distributions correlated to the expected intrinsic moment distribution of the cores. Additional peaks were observed which signaled deviations of the isothermal magnetisation behavior from the non-interacting case, indicating weak dipolar interactions.
authors.affiliation: Department CITIMAC, Faculty of Science, University of Cantabria, 39005 Santander, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Bender
authors.affiliation: Healthcare Biomagnetics Laboratory, University College London, 21 Albemarle Street, London, W1S 4BS, UK.
authors.forename: L K
authors.initials: LK
authors.lastname: Bogart
authors.affiliation: Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Posth
authors.affiliation: Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany.|Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Krakow, Poland.
authors.forename: W
authors.initials: W
authors.lastname: Szczerba
authors.affiliation: ISIS-STFC Neutron Scattering Facility, Harwell Science and Innovation Campus, Didcot, OXON, OX11 0QX, UK.
authors.forename: S E
authors.initials: SE
authors.lastname: Rogers
authors.affiliation: SOLVE Research and Consultancy AB, Lund, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Castro
authors.affiliation: SOLVE Research and Consultancy AB, Lund, Sweden.|Lund Centre for Field-Flow Fractionation, Department of Food Technology, Engineering and Nutrition, Lund University, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Nilsson
authors.affiliation: Department of Physics, Chalmers University of Technology, 41296 Göteborg, Sweden.
authors.forename: L J
authors.initials: LJ
authors.lastname: Zeng
authors.affiliation: SP Technical Research Institute of Sweden, Chemistry, Materials and Surfaces Unit, 11486 Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Sugunan
authors.affiliation: SP Technical Research Institute of Sweden, Chemistry, Materials and Surfaces Unit, 11486 Stockholm, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Sommertune
authors.affiliation: SP Technical Research Institute of Sweden, Chemistry, Materials and Surfaces Unit, 11486 Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Fornara
authors.affiliation: Department CITIMAC, Faculty of Science, University of Cantabria, 39005 Santander, Spain.
authors.forename: D
authors.initials: D
authors.lastname: González-Alonso
authors.affiliation: Department CITIMAC, Faculty of Science, University of Cantabria, 39005 Santander, Spain.
authors.forename: L Fernández
authors.initials: LF
authors.lastname: Barquín
authors.affiliation: RISE Acreo, 40014 Göteborg, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Johansson