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Title: Iron oxide nanoparticles: the Influence of synthesis method and size on composition and magnetic properties

Abstract

Iron oxide nanoparticles with mean diameter ranging from 7 to 20 nm were synthesized using two routes: the precipitation method in controlled atmosphere and a reduction–precipitation method under air, in some cases followed by a hydrothermal treatment. The smallest nanoparticles were obtained by the reduction–precipitation method. In order to establish the composition of the iron oxide nanoparticles and its relation with size, the morphological, structural and magnetic properties of the prepared samples were investigated using X-ray diffraction, transmission electron microscopy, Mössbauer spectroscopy and SQUID magnetometry. The results allow to conclude that the nanoparticles can be essentially described as Fe 3–xO₄, x decreasing with the particle size increase. The composition and magnetic behavior of the synthesized iron oxide nanoparticles are directly related with their size. The overall results are compatible with a core@shell structure model, where a magnetite core is surrounded by an oxidized magnetite layer (labeled as maghemite), the magnetite core dimension depending on the average particle size. - Graphical abstract: TEM images and Mössbauer spectroscopy spectra of Fe 3–xO₄ samples with different sizes. Highlights: • Fe 3–xO₄ nanoparticles with a mean size between 7 and 20 nm were synthesized. • The smallest nanoparticles were obtained by a reduction precipitationmore » method, under air. • The increase of particles size was succeeded using a hydrothermal treatment at 150 °C. • The magnetic properties of the nanoparticles are directly related with their size.« less

Authors:
 [1];  [2]; ;  [2]
  1. CCMM/Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, C8, 1749-016 Lisboa (Portugal)
  2. CFMC/Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa (Portugal)
Publication Date:
OSTI Identifier:
22306279
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 201; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 77 NANOSCIENCE AND NANOTECHNOLOGY; CONTROLLED ATMOSPHERES; IRON OXIDES; MAGNETIC PROPERTIES; MAGNETITE; NANOPARTICLES; PARTICLE SIZE; PRECIPITATION; SPECTRA; SPECTROSCOPY; SYNTHESIS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION

Citation Formats

Carvalho, M.D., E-mail: mdcarvalho@fc.ul.pt, Henriques, F., Ferreira, L. P., Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-516 Coimbra, Godinho, M., and Cruz, M. M. Iron oxide nanoparticles: the Influence of synthesis method and size on composition and magnetic properties. United States: N. p., 2013. Web. doi:10.1016/J.JSSC.2013.02.024.
Carvalho, M.D., E-mail: mdcarvalho@fc.ul.pt, Henriques, F., Ferreira, L. P., Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-516 Coimbra, Godinho, M., & Cruz, M. M. Iron oxide nanoparticles: the Influence of synthesis method and size on composition and magnetic properties. United States. doi:10.1016/J.JSSC.2013.02.024.
Carvalho, M.D., E-mail: mdcarvalho@fc.ul.pt, Henriques, F., Ferreira, L. P., Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-516 Coimbra, Godinho, M., and Cruz, M. M. Wed . "Iron oxide nanoparticles: the Influence of synthesis method and size on composition and magnetic properties". United States. doi:10.1016/J.JSSC.2013.02.024.
@article{osti_22306279,
title = {Iron oxide nanoparticles: the Influence of synthesis method and size on composition and magnetic properties},
author = {Carvalho, M.D., E-mail: mdcarvalho@fc.ul.pt and Henriques, F. and Ferreira, L. P. and Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-516 Coimbra and Godinho, M. and Cruz, M. M.},
abstractNote = {Iron oxide nanoparticles with mean diameter ranging from 7 to 20 nm were synthesized using two routes: the precipitation method in controlled atmosphere and a reduction–precipitation method under air, in some cases followed by a hydrothermal treatment. The smallest nanoparticles were obtained by the reduction–precipitation method. In order to establish the composition of the iron oxide nanoparticles and its relation with size, the morphological, structural and magnetic properties of the prepared samples were investigated using X-ray diffraction, transmission electron microscopy, Mössbauer spectroscopy and SQUID magnetometry. The results allow to conclude that the nanoparticles can be essentially described as Fe3–xO₄, x decreasing with the particle size increase. The composition and magnetic behavior of the synthesized iron oxide nanoparticles are directly related with their size. The overall results are compatible with a core@shell structure model, where a magnetite core is surrounded by an oxidized magnetite layer (labeled as maghemite), the magnetite core dimension depending on the average particle size. - Graphical abstract: TEM images and Mössbauer spectroscopy spectra of Fe3–xO₄ samples with different sizes. Highlights: • Fe3–xO₄ nanoparticles with a mean size between 7 and 20 nm were synthesized. • The smallest nanoparticles were obtained by a reduction precipitation method, under air. • The increase of particles size was succeeded using a hydrothermal treatment at 150 °C. • The magnetic properties of the nanoparticles are directly related with their size.},
doi = {10.1016/J.JSSC.2013.02.024},
journal = {Journal of Solid State Chemistry},
issn = {0022-4596},
number = ,
volume = 201,
place = {United States},
year = {2013},
month = {5}
}