Abstract
Iron oxide magnetic nanoparticles produced by chemical synthesis are usually composed of both magnetite and maghemite phases. Information about the phase composition is typically obtained using Mössbauer spectroscopy. A method that can provide information about the magnetite versus maghemite phase composition of the nanoparticles and the organization of the phases simply from magnetization curve is still missing. Here we present a simple and elegant method that for nanoparticles with a known size distribution can give information about the magnetite and maghemite phase composition and suggests a magnetite core and a maghemite shell structure for all the nanoparticles sizes. The method is based on fitting of the room-temperature magnetization curve using a Brillouin function, while considering dipolar interactions. The model predicts that the nanoparticles are composed of a single magnetic domain for sizes below 14 nm. The model is validated by Mössbauer spectroscopy.
Original language | English |
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Pages (from-to) | 28292-28301 |
Number of pages | 10 |
Journal | Journal of Physical Chemistry C |
Volume | 122 |
Issue number | 49 |
DOIs | |
Publication status | Published - 13 Dec 2018 |
Funding
The authors acknowledge the financial support from the Max-Planck Institute for Polymer Research (Mainz, Germany). The authors would like to acknowledge Prof. W. Tremel and Anielen Halda Ribeiro for fruitful discussions, Frank Keller, Michelle Beuchel, Christian Bauer and Verona Maus for their technical helps. K.A. acknowledges the Alexander von Humboldt Foundation for funding provided in the framework of the Sofja Kovalevskaja Award endowed by the Federal Ministry of Education and Research, Germany. A.M. acknowledges funding by the Carl-Zeiss Foundation (Stiftungspro-fessur für Oxidische Materialien).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- General Energy
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films