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

doi:10.1016/j.jssc.2013.03.018

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

Research output: Contribution to journal › Article › peer-review

32 Scopus citations

Abstract

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 Fe 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 Eu³⁺ ions, characterized by a higher one-ion anisotropy and a lower magnetic moment with respect to iron cations.

Original language	English
Pages (from-to)	302-311
Number of pages	10
Journal	Journal of Solid State Chemistry
Volume	201
DOIs	https://doi.org/10.1016/j.jssc.2013.03.018
State	Published - May 2013
Externally published	Yes

Bibliographical note

Funding Information:
Research supported in part by ONRMURIN000140810747, and AFOR’s complex networks program.

Funding Information:
★ Research supported in part by ONR MURI N000140810747, networks program.

Keywords

Europium
Hematite
Magnetic properties
Nanoparticles
Rare-earths

Access to Document

10.1016/j.jssc.2013.03.018

Cite this

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title = "Eu-doped α-Fe2O3 nanoparticles with modified magnetic properties",

abstract = "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 Fe 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 Eu3+ ions, characterized by a higher one-ion anisotropy and a lower magnetic moment with respect to iron cations.",

keywords = "Europium, Hematite, Magnetic properties, Nanoparticles, Rare-earths",

author = "Freyria, {Francesca Stefania} and Gabriele Barrera and Paola Tiberto and Elena Belluso and Davide Levy and Guido Saracco and Paolo Allia and Edoardo Garrone and Barbara Bonelli",

note = "Funding Information: Research supported in part by ONRMURIN000140810747, and AFOR{\textquoteright}s complex networks program. Funding Information: ★ Research supported in part by ONR MURI N000140810747, networks program.",

year = "2013",

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doi = "10.1016/j.jssc.2013.03.018",

language = "אנגלית",

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T1 - Eu-doped α-Fe2O3 nanoparticles with modified magnetic properties

AU - Freyria, Francesca Stefania

AU - Barrera, Gabriele

AU - Tiberto, Paola

AU - Belluso, Elena

AU - Levy, Davide

AU - Saracco, Guido

AU - Allia, Paolo

AU - Garrone, Edoardo

AU - Bonelli, Barbara

N1 - Funding Information: Research supported in part by ONRMURIN000140810747, and AFOR’s complex networks program. Funding Information: ★ Research supported in part by ONR MURI N000140810747, networks program.

PY - 2013/5

Y1 - 2013/5

N2 - 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 Fe 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 Eu3+ ions, characterized by a higher one-ion anisotropy and a lower magnetic moment with respect to iron cations.

AB - 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 Fe 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 Eu3+ ions, characterized by a higher one-ion anisotropy and a lower magnetic moment with respect to iron cations.

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