title: Magneto-optical characterization of colloidal dispersions. Application to nickel nanoparticles.
abstract: We report here on a fast magneto-optical characterization method for colloidal liquid dispersions of magnetic nanoparticles. We have applied our methodology to Ni nanoparticles with size equal or below 15 nm synthesized by a ligand stabilized solution-phase synthesis. We have measured the magnetic circular dichroism (MCD) of colloidal dispersions and found that we can probe the intrinsic magnetic properties within a wide concentration range, from 10(-5) up to 10(-2) M, with sensitivity to concentrations below 1 microg/mL of magnetic Ni particles. We found that the measured MCD signal scales up with the concentration thus providing a means of determining the concentration values of highly diluted dispersions. The methodology presented here exhibits large flexibility and versatility and might be suitable to study either fundamental problems related to properties of nanosize particles including surface related effects which are highly relevant for magnetic colloids in biomedical applications or to be applied to in situ testing and integration in production lines.
authors.affiliation: Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Catalonia, Spain.
authors.forename: Oana
authors.initials: O
authors.lastname: Pascu
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Caicedo
authors.forename: Josep
authors.initials: J
authors.lastname: Fontcuberta
authors.forename: Gervasi
authors.initials: G
authors.lastname: Herranz
authors.forename: Anna
authors.initials: A
authors.lastname: Roig
mesh_terms: D002942:Circular Dichroism; D003102:Colloids / Q000737:chemistry*; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D009532:Nickel / Q000737:chemistry*
chemical_list: D003102:Colloids; D009532:Nickel