Eu-doping of hematite (α-Fe2O3) nanoparticles (NPs) takes place under hydrothermal conditions, and does not at ambient temperature and pressure. Required circumstances have been studied in detail. In the presence of Eu, besides hematite, some goethite and ferrihydrite are formed. Evidence for the occurrence of doping is reported. Chemical composition, as studied by EDS (bulk) and XPS (surface), reveals an enrichment of Eu at NPs core, ascribed to the occurrence of a two-step mechanism of NP formation, comprising nucleation at first, in which Eu3+ ions compete with Fe3+ ions, notwithstanding the large difference in concentration, and a successive growth step of NPs in a solution comparatively richer in Fe3+ species. The Eu content affects: (i) the morphology of NPs, as shown by TEM and FE-SEM; (ii) lattice parameters, as obtained by Rietveld refinement of XRD patterns; (iii) magnetic properties, due to the presence of Eu3+ ions, characterized by a higher one-ion anisotropy and a lower magnetic moment with respect to iron cations.
Eu-doped α-Fe2O3 nanoparticles with modified magnetic properties / Francesca Stefania Freyria; Gabriele Barrera; Paola Tiberto; Elena Belluso; Davide Levy; Guido Saracco; Paolo Allia; Edoardo Garrone; Barbara Bonelli. - In: JOURNAL OF SOLID STATE CHEMISTRY. - ISSN 0022-4596. - STAMPA. - 201(2013), pp. 302-311.
|Titolo:||Eu-doped α-Fe2O3 nanoparticles with modified magnetic properties|
|Data di pubblicazione:||2013|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.jssc.2013.03.018|
|Appare nelle tipologie:||1.1 Articolo in rivista|
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