Abstract

Monodisperse cubic spinel iron oxide magnetic nanoparticles with variablesizes were prepared following a multi-injection seeded-growth approach. As expectedfrom such a well-known synthetic route, all samples were characterized by narrow sizedistributions, and showed excellent stability in both organic and aqueous media withoutthe presence of aggregates, thus becoming ideal candidates for the study of theirhyperthermia performance. Specific Loss Power measurements indicated low heatingpowers for all samples without a maximum for any specific size, contrary to what theorypredicts. The magnetic study showed the formation of size-dependent nonsaturatedmagnetic regions, which enlarged with the particle size, evidencing a clear discrepancybetween the crystal size and the effective magnetic volume. Strain map analysis of highresolution transmission electron micrographs indicated the presence of highly strainedcrystal areas even if nanoparticles were monocrystalline. The origin of the crystal strainwas found to be strictly correlated with the seeded-growth synthetic procedure used forthe preparation of the nanoparticles, which turned out to alter their magnetic structure by creating antiphase boundaries.Considering the calculated effective magnetic volumes and their magnetic dispersions in each sample, a reasonable agreementbetween hyperthermia experiments and theory was obtained.

Autore Pugliese

• Quarta Alessandra

Tutti gli autori

• Levy M.; Quarta A.; Espinosa A.; Figuerola A.;Wilhelm C.; García-Hernandez M.; Genovese A.; Falqui A.;Alloyeau D.; Buonsanti R.; Cozzoli P.D.; García M.A.; Gazeau F.; Pellegrino T.

Titolo volume/Rivista

Chemistry of materials

Anno di pubblicazione

2011

ISSN

0897-4756

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

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Numero di citazioni Scopus

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Ultimo Aggiornamento Citazioni

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Settori ERC

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Codici ASJC

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