Počet záznamů: 1  

Magnetic properties of TCr2O4 (T = Co, Ni) fine powders and TCr2O4/SiO2 nanocomposites

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    0435626 - ÚACH 2015 RIV GB eng C - Konferenční příspěvek (zahraniční konf.)
    Mantlíková, A. - Vejpravová, J.P. - Holec, Petr - Plocek, Jiří - Nižňanský, D.
    Magnetic properties of TCr2O4 (T = Co, Ni) fine powders and TCr2O4/SiO2 nanocomposites.
    IOP conference series: Materials science and engineering. Vol. 18. Bristol: IOP Publishing, 2011, 032022. Symposium. ISSN 1757-8981.
    [International Congress on Ceramics /3./. Osaka (JP), 14.11.2010-18.11.2010]
    Grant CEP: GA ČR GAP108/10/1250
    Klíčová slova: NICR2O4 * nanocomposites
    Kód oboru RIV: CA - Anorganická chemie

    We have studied magnetic properties of TCr2O4 (T = Co, Ni) fine powders, obtained by the citric acid method, and TCr2O4/SiO2 nanocomposites, constituted of spinel nanoparticles embedded in silica matrix fabricated by a modified sol gel method. All samples were characterized by powder X-ray diffraction, scanning electron microscopy and microprobe analysis. The profile analysis of the powder X-ray diffraction revealed that the particle size is larger for the fine powder samples, as expected. Detailed measurements of magnetization, hysteresis loops and a.c. susceptibility demonstrate significant differences in magnetic properties of the fine powders in comparison to the nanocomposite samples. The values of the coercitivity at 10 K ranges from approximate to 2T for NiCr2O4 fine powders to approximate to 0.6 T for CoCr2O4/SiO2 nanocomposites. Moreover, the hysteresis loops of the NiCr2O4/SiO2 samples are brightly asymmetric. The phenomenon will be discussed in context of the exchange-bias originated by presence of a tiny amount of the antiferromagnetic phase, Cr2O3 in the samples.
    Trvalý link: http://hdl.handle.net/11104/0245456

     
     
Počet záznamů: 1  

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