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    Magnetic, structural, and electronic properties of iron sulfide Fe3S4 nanoparticles synthesized by the polyol mediated process / I. S. Lyubutin [et al.] // J. Nanopart. Res. - 2013. - Vol. 15. - P. 1397DOI 10.1007/s11051-012-1397-0
   Перевод заглавия: Магнитные, структурные и электронные свойства наночастиц сульфида железа Fe3S4, полученных полиол-синтезом
Аннотация: Iron sulfide nanoparticles Fe3S4 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 Fe3S4 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 μB per Fe3S4 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 Fe3+ ⇆ Fe2+ 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 Fe3S4 for the first time. The spectra differ substantially from that of the isostructural oxide Fe3O4. 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.

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Держатели документа:
Russian Acad Sci, AV Shubnikov Crystallog Inst, Moscow 119333, Russia
Southern Taiwan Univ Sci & Technol, Dept Mech Engn, Inst Nanotechnol, Tainan 710, Taiwan
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
Siberian Fed Univ, Inst Engn Phys & Radioelect, Krasnoyarsk 660041, Russia

Доп.точки доступа:
Lyubutin, I. S.; Starchikov, S. S.; Lin, Chun-Rong; Lu, Shin-Zong; Shaikh, M. O.; Funtov, K. O.; Dmitrieva, T. V.; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Edelman, I. S.; Ivantsov, R. D.; Иванцов, Руслан Дмитриевич
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2.


   
    Effect of molecular weight of sodium polyacrylates on the size and morphology of nickel nanoparticles synthesized by the modified polyol method and their magnetic properties / O. A. Logutenko [et al.] // Eur. Polym. J. - 2018. - Vol. 99. - P. 102-110, DOI 10.1016/j.eurpolymj.2017.12.017. - Cited References: 26. - This work was supported by the Russian Science Foundation, research project No. 15-13-00113. . - ISSN 0014-3057
Кл.слова (ненормированные):
Nickel nanoparticles -- Sodium polyacrylate -- Polyol -- Reduction -- Magnetic properties
Аннотация: Nickel nanoparticles were synthesized by the reduction of nickel chloride with hydrazine hydrate in a polyol medium in the presence of sodium polyacrylates (Na-PA) having molecular weights (Mw) of 1200, 5100 and 8000. The size and morphology of the resulting nickel nanoparticles were characterized by X-ray diffraction, scanning and transmission electron microscopy. Polymers having lower Mw values were found to be more efficient in reducing the nickel particle size. A decrease in the polymer concentrations yielded the smaller particles. Magnetic measurements showed that the as-prepared powders are ferromagnetic and their saturation magnetization and coercivity are size-dependent. Compared with bulk nickel, the nanoparticles exhibit an enhanced coercivity which is due to their small size and a decreased saturation magnetization resulted from the surface oxidation of the powder. The synthesis procedure offers a simple approach to preparing nickel nanopowders on a large scale which could be used as magnetic recording materials, including high-density memory storage devices.

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Держатели документа:
Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Kutateladze, 18, Novosibirsk, Russian Federation
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Academgorodok, 50/12, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Logutenko, O. A.; Titkov, A. I.; Vorob'yov, A. M.; Balaev, D. A.; Балаев, Дмитрий Александрович; Shaikhutdinov, K. A.; Шайхутдинов, Кирилл Александрович; Semenov, S. V.; Семёнов, Сергей Васильевич; Yukhin, Y. M.; Lyakhov, N. Z.
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