000203223 001__ 203223
000203223 005__ 20181203023650.0
000203223 0247_ $$2doi$$a10.1063/1.4895837
000203223 022__ $$a0021-8979
000203223 02470 $$2ISI$$a000342837000027
000203223 037__ $$aARTICLE
000203223 245__ $$aFe3O4 nanoparticles and nanocomposites with potential application in biomedicine and in communication technologies: Nanoparticle aggregation, interaction, and effective magnetic anisotropy
000203223 260__ $$aMelville$$bAmerican Institute of Physics$$c2014
000203223 269__ $$a2014
000203223 300__ $$a9
000203223 336__ $$aJournal Articles
000203223 520__ $$aMagnetite nanoparticles with a size of 5-6 nm with potential impact on biomedicine and information/communication technologies were synthesized by thermal decomposition of Fe(acac)(3) and subsequently coated with a silica shell exploiting a water-in-oil synthetic procedure. The as-produced powders (comprised of either Fe3O4 or Fe3O4@silica nanoparticles) were mixed with a photocurable resin obtaining two magnetic nanocomposites with the same nominal amount of magnetic material. The static magnetic properties of the two nanopowders and the corresponding nanocomposites were measured in the 10 K-300 K temperature range. Magnetic measurements are shown here to be able to give unambiguous information on single-particle properties such as particle size and magnetic anisotropy as well as on nanoparticle aggregation and interparticle interaction. A comparison between the size distribution functions obtained from magnetic measurements and from TEM images shows that figures estimated from properly analyzed magnetic measurements are very close to the actual values. In addition, the present analysis allows us to determine the value of the effective magnetic anisotropy and to estimate the anisotropy contribution from the surface. The Field-cooled/ zero field cooled curves reveal a high degree of particle aggregation in the Fe3O4 nanopowder, which is partially reduced by silica coating and strongly decreased by dissolution in the host polymer. In all considered materials, the nanoparticles are magnetically interacting, the interaction strength being a function of nanoparticle environment and being the lowest in the nanocomposite containing bare, well-separate Fe3O4 particles. All samples behave as interacting superparamagnetic materials instead of ideal superparamagnets and follow the corresponding scaling law. (C) 2014 AIP Publishing LLC.
000203223 700__ $$aAllia, P.$$uPolitecn Torino, DISAT, I-1029 Turin, Italy
000203223 700__ $$aBarrera, G.$$uUniv Turin, Dept Chem, I-10125 Turin, Italy
000203223 700__ $$aTiberto, P.$$uINRiM, Electromagnetism Div, I-10135 Turin, Italy
000203223 700__ $$aNardi, T.
000203223 700__ $$0240315$$aLeterrier, Y.$$g105657
000203223 700__ $$aSangermano, M.$$uPolitecn Torino, DISAT, I-1029 Turin, Italy
000203223 773__ $$j116$$k11$$tJournal of Applied Physics
000203223 909C0 $$0252013$$pLTC$$xU10339
000203223 909CO $$ooai:infoscience.tind.io:203223$$particle
000203223 917Z8 $$x105657
000203223 937__ $$aEPFL-ARTICLE-203223
000203223 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000203223 980__ $$aARTICLE