Preparation of magnetite nanoparticles by thermal decomposition of hematite powder in the presence of organic solvent

Chun Rong Lin, Ray Kuang Chiang, Chih Jung Chen, Steven Hsin-Yi Lai, Igor S. Lyubutin, Egor A. Alkaev

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)

Abstract

Magnetite nanoparticles have been synthesized by thermal decomposition of hematite (oe-Fe203) powder in the presence of high boiling point solvent. The mixture of hematite and 1-octadecene solvent was heated and stirred in nitrogen gas at the temperature of 320 °C for the desired time (~2 to 28 hrs). The influence of the reaction time on transformation process was analyzed with X-ray diffraction (XRD), M5ssbauer spectroscopy (MS), and magnetic measurements. XRD patterns show that the phase of intermediate was composed of spinel phase and corundum phase (a-Fe203). The 57Fe Mossbauer spectra show that the spinel phase originated from the magnetite particles. The structure transformation proportion of hematite to magnetite strongly depends on reaction times. After reflux for 28 hrs the hematite-magnetite transformation was complete. The mean crystallite size of pure phase of magnetite particles is about 40 nm. The saturation magnetization increases with the reaction time, which corresponds to an increase of concentration of magnetite in the samples. A pronounced feature of the Hc and GrlGs observed in samples is the steplike change which appears at 125 K and is characteristic of the Verwey transition. The hyperfine parameters of Mossbauer spectrum measured at low temperature also indicate that the Verwey phase transition occurs. In other words, the Verwey transition is an indication that the magnetite particles exactly grew up in the synthesized compounds. This thermal decomposition process provided a method to prepare pure magnetite as well as magnetite/hematite nanocomposites useful for various magnetic applications.

Original languageEnglish
Title of host publicationMaterials Research Society Symposium Proceedings - Nanoscale Magnetics and Device Applications
Pages115-123
Number of pages9
Publication statusPublished - 2007 Dec 1
EventNanoscale Magnetics and Device Applications - 2007 MRS Spring Meeting - San Francisco, CA, United States
Duration: 2007 Apr 92007 Apr 13

Publication series

NameMaterials Research Society Symposium Proceedings
Volume998
ISSN (Print)0272-9172

Other

OtherNanoscale Magnetics and Device Applications - 2007 MRS Spring Meeting
CountryUnited States
CitySan Francisco, CA
Period07-04-0907-04-13

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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