title: Fabrication and magnetic properties of Ni nanospheres encapsulated in a fullerene-like carbon.
abstract: A very simple, efficient, and economical synthetic technique, which produces fascinating fullerene-like Ni-C (graphitic) core-shell nanostructures at a relatively low temperature, is reported. The thermal dissociation of Ni acetylacetonate is carried out in a closed vessel cell (Swagelok) that was heated at 700 degrees C for 3 h. The encapsulation of ferromagnetic Ni nanospheres into the onion structured graphitic layers is obtained in a one-stage, single precursor reaction, without a catalyst, that possesses interesting magnetic properties. The magnetoresistance (MR) property of Ni nanospheres encapsulated in a fullerene-like carbon was measured, which shows large negative MR, of the order of 10%. The proposed mechanism for the formation of the Ni-C core-shell system is based on the segregation and the surface flux formed in the Ni and carbon particles during the reaction under autogenic pressure at elevated temperature.
authors.affiliation: Department of Chemistry and Kanbar Laboratory for Nanomaterials at the Bar-Ilan University Center for Advanced Materials and Nanotechnology, Bar-Ilan University, Ramat-Gan, 52900, Israel.
authors.forename: S V
authors.initials: SV
authors.lastname: Pol
authors.forename: V G
authors.initials: VG
authors.lastname: Pol
authors.forename: A
authors.initials: A
authors.lastname: Frydman
authors.forename: G N
authors.initials: GN
authors.lastname: Churilov
authors.forename: A
authors.initials: A
authors.lastname: Gedanken
mesh_terms: D002244:Carbon / Q000737:chemistry*; D004574:Electromagnetic Fields; D037741:Fullerenes / Q000737:chemistry*; D006358:Hot Temperature; D007202:Indicators and Reagents; D008280:Magnetics; D046529:Microscopy, Electron, Transmission; D043942:Nanotubes; D009532:Nickel / Q000737:chemistry*; D011312:Pressure; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction
chemical_list: D037741:Fullerenes; D007202:Indicators and Reagents; D002244:Carbon; D009532:Nickel