Details

Autor(en) / Beteiligte

• Lyubutin, I. S.
• Starchikov, S. S.
• Lin, Chun-Rong
• Lu, Shin-Zong
• Shaikh, Muhammad Omar
• Funtov, K. O.
• Dmitrieva, T. V.
• Ovchinnikov, S. G.
• Edelman, I. S.
• Ivantsov, R.

Titel

Magnetic, structural, and electronic properties of iron sulfide Fe3S4 nanoparticles synthesized by the polyol mediated process

Ist Teil von

• Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology, 2013, Vol.15 (1), Article 1397

Ort / Verlag

Dordrecht: Springer Netherlands

Erscheinungsjahr

2013

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Iron sulfide nanoparticles Fe 3 S 4 with the spinel-type crystal structure were synthesized by the polyol mediated process. The particle size depends on preparation conditions and varies from 9 to 20 nm. Mössbauer data have revealed that the dominating fraction of iron ions in the 9-nm sample is in the high-spin ferric state. This implies an occurrence of the cation vacancies in nonstoichiometric greigite. The stoichiometric phase of greigite Fe 3 S 4 dominates in the 18-nm-size nanoparticles. Magnetic measurements have shown a ferrimagnetic behavior of all samples at temperatures between 78 and 300 K. The estimated value of magnetic moment of the stoichiometric greigite nanoparticles is about 3.5 μ B per Fe 3 S 4 unit. The Mössbauer spectra indicate a superparamagnetic behavior of small particles, and some fraction of superparamagnetic phase is observed in all samples synthesized which may be caused by the particle size distribution. The blocking temperatures of T B  ≈ 230 and 250 K are estimated for the 9 and 14 nm particles, respectively. The Mössbauer parameters indicate a great degree of covalency in the Fe–S bonds and support the fast electron Fe 3+  ⇆ Fe 2+ exchange in the B-sites of greigite. An absence of the Verwey transition at temperatures between 90 and 295 K is established supporting a semimetal type of conductivity. The temperature and magnetic field dependences of the magnetic circular dichroism (MCD) of optical spectra were measured in Fe 3 S 4 for the first time. The spectra differ substantially from that of the isostructural oxide Fe 3 O 4 . It is supposed that the MCD spectra of greigite nanoparticles result from the collective electron excitations in a wide band with superimposed peaks of the d – d transitions in Fe ions.