Parametric Rietveld refinement and magnetic characterization of superparamagnetic iron oxide nanoparticles

Parametric Rietveld refinement and magnetic characterization of superparamagnetic iron oxide nanoparticles

Author Pereira, Guilherme Ferreira Lemos Autor UNIFESP Google Scholar
Costa, Fanny Nascimento Google Scholar
Souza, Jose Antonio Google Scholar
Haddad, Paula Silvia Autor UNIFESP Google Scholar
Ferreira, Fabio Furlan Google Scholar
Abstract This article describes the synthesis of two superparamagnetic iron oxide nanoparticles (SPIONs) covered with different ligands - hydrophobic (oleic acid (OA)) and hydrophilic (tetraethyl ammonium (TEA)) - and the investigation of the effects of thermal treatments on the crystal structure of TEA-SPIONs or OA-SPIONs using X-ray powder diffraction data and parametric Rietveld refinements

we stablished non-crystallographic models to describe how the oxidation processes take place with increasing temperatures for the different systems. The morphological and magnetic properties revealed the nanoparticles have a mean diameter of similar to 10 nm in the solid state and are superparamagnetic at room temperature. Magnetization measurements confirmed the superparamagnetic state for both systems and revealed smaller particle sizes and narrower size distribution for OA-SPIONs than for TEA-SPIONs. The thermomagnetic analyses show only the ferrimagnetic phase transition of magnetite for OA-SPIONs while in the TEA-SPIONs, besides the ferrimagnetic phase transition there is the appearance of an antiferromagnetic one disclosing the evolution of hematite phase probably on the surface of magnetite due to thermal cycles. (C) 2018 Elsevier B.V. All rights reserved.
Keywords Superparamagnetic iron oxide nanoparticles
X-ray powder diffraction
Parametric Rietveld refinements
Magnetic measurements
Language English
Sponsor CNPq
Grant number CNPq: 402289/2013-7
CNPq: 307664/2015-5
FAPESP: 2014/13913-7
FAPESP: 2014/20228-9
Date 2018
Published in Journal Of Magnetism And Magnetic Materials. Amsterdam, v. 456, p. 108-117, 2018.
ISSN 0304-8853 (Sherpa/Romeo, impact factor)
Publisher Elsevier Science Bv
Extent 108-117
Access rights Closed access
Type Article
Web of Science ID WOS:000427580800017

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