Eu-doped α-Fe{sub 2}O{sub 3} nanoparticles with modified magnetic properties

Journal Article · Wed May 15 00:00:00 EDT 2013 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2013.03.018· OSTI ID:22306300

Freyria, Francesca Stefania ^[1]; Barrera, Gabriele; Tiberto, Paola ^[2]; Belluso, Elena ^[3]; Levy, Davide ^[3]; Saracco, Guido; Allia, Paolo; Garrone, Edoardo ^[1]; Bonelli, Barbara ^[1]

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1. Department of Applied Science and Technology and INSTM Unit-Torino Politecnico, Corso Duca degli Abruzzi 24, Politecnico di Torino, I-10129 Turin (Italy)
2. Electromagnetism Department, INRIM, Strada delle Cacce 91, I-10135 Turin (Italy)
3. Earth Science Department, Università degli Studi di Torino, Via Valperga Caluso 35, I-10125 Turin (Italy)

Eu-doping of hematite (α-Fe{sub 2}O{sub 3}) 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 Eu{sup 3+} ions compete with Fe{sup 3+} ions, notwithstanding the large difference in concentration, and a successive growth step of NPs in a solution comparatively richer in Fe{sup 3+} 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 Eu{sup 3+} ions, characterized by a higher one-ion anisotropy and a lower magnetic moment with respect to iron cations. - Graphical abstract: Eu-doped α-Fe{sub 2}O{sub 3} NPs are obtained by forced hydrolysis under hydrothermal conditions: changes are observed in NPs morphology, lattice parameters and magnetic properties. - Highlights: • Eu-doped hematite NPs were prepared by forced hydrolysis. • Eu ions affect NPs morphology and lattice parameters. • Eu ions affect the magnetic properties of hematite NPs. • Doped NPs have a Eu-richer core.

• OSTI ID: 22306300
• Journal Information: Journal of Solid State Chemistry, Vol. 201; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
77 NANOSCIENCE AND NANOTECHNOLOGY
CATIONS
DOPED MATERIALS
EUROPIUM
EUROPIUM IONS
FERRITES
GOETHITE
HEMATITE
HYDROLYSIS
IRON IONS
IRON OXIDES
LATTICE PARAMETERS
MAGNETIC PROPERTIES
NANOPARTICLES
SCANNING ELECTRON MICROSCOPY
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY