Nanocomposites and nanomaterials

Core/shell architecture as an efficient tool to tune DC magnetic parameters and AC losses in spinel ferrite nanoparticles
Solopan S.O.1, Nedelko N.2, Lewinska S.2, Ślawska-Waniewska A.2, 
Zamorskyi V.O. 3, Tovstolytkin A.I.4, Belous A.G. 1
1V.I. Vernadsky Institute of General and Inorganic Chemistry of the NAS of Ukraine, 32/34 Palladina Ave., Kyiv 03142, Ukraine.
E-mail: solopan@ukr.net 
2Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland.
3Faculty of Radiophysics, Electronics and Computer Systems, Taras Shevchenko National University of Kyiv, 4G Glushkova Ave., Kyiv 03680, Ukraine.
4Institute of Magnetism of the NAS of Ukraine and MES of Ukraine, 36-b 
Vernadsky Blvd., Kyiv 03142, Ukraine.

Core/shell architecture has acquired increasing interest due to the possibility of combining different materials and fabricating nanostructures with improved characteristics. Recent studies have shown some merits of this architecture in optimizing the parameters of nanoparticles for biomedical applications, in particular for magnetic hyperthermia [1]. This work is aimed at clarification of the regularities of the effects of nanoparticle coating on the transformation of DC and AC magnetic responses in composite spinel ferrite nanoparticles which are promising for nanohyperthermia applications.
Two sets of core/shell nanoparticles, CoFe2O4/Fe3O4 and Fe3O4/CoFe2O4, with a fixed diameter of core (~5 nm) and thickness of shells up to 2.5 nm were synthesized from metal chlorides [1] and characterized by X-ray diffraction, transmission electron microscopy, magnetic and calorimetric measurements. A comprehensive analysis of experimental data accompanied by a proper numerical simulation made it possible to clarify the effect of core/shell architecture on transformation of DC magnetic parameters and AC energy losses in the nanoparticles under investigation.
The results obtained are useful for tailoring the parameters of core/shell spinel nanoferrites for their use in a number of technological and medical applications.

1.	Yelenich O.V., Solopan S.O, et al. Synthesis and properties of MFe2O4 (M = Fe, Co) nanoparticles and core-shell structures // Sol St Sci. - 2015. - 46. - P. 19-26.