Nanocomposites and nanomaterials

Electro-transport properties of nanocarbon structures modidfied with nickel and iron
Syvolozhskyi O.A.1, Ovsiienko I.V.1, Matzui L.Yu.1, Dyachenko A.G.2, Ischenko O.V.2, Yakovenko O.S.1, Len T.A.1, Borovoy M.O.1, Tesel'ko P.O.1

Taras Shevchenko National University of Kyiv, 01601, Kyiv, Volodymyrska st. 64/13, Department of Physics1 and Chemistry2
E-mail: mail.olexiy@gmail.com

In the present work the questions of creation and investigations of new multicomponent nanocomposites based on nanocarbon structure are considered. The two types of nanocarbon structures were used as source materials for obtaining the nanocomposites. These are nanographite platelets obtained by sonication of thermoexfoliated graphite in acetone and multiwall carbon nanotubes (CNTs) obtained by arc-method. The modification of the nanocarbon particles has been carried out with method of reducing the metal from the water-salt solution in the stream of the mixture of gaseous helium and hydrogen. The structure and phase composition of obtained multicomponent nanomaterials have been investigated by X-R diffraction and electron microscopy methods. The structural studies have found that the obtained nanocomposites contain metal particles in diameter ~ 100 nm (80% mas. Ni  20% mas Fe) that are uniformly distributed along the surface of the nanocarbon. For investigations of resistivity (T) and magnetoresistance /(T, B) bulk specimens from modified nanocarbon structures have been prepared by cold compacting with use PVA as binder.
Figure 1 presents the dependences /(B) for bulk specimens of modifided nanographite platelets (a) and CNTs (b) at different temperatures.
a)	b)	As can be seen from Figure for modified nanographite platelets the dependence /(B) is quadratic and weekly dependent on temperature. For modified carbon nanotubes hysteresis in the /(B) dependence at room temperature	
Fig. 1. /(B) for modifided nanographite platelets (a) and CNTs (b), 1 – T = 293 K, 2 – T = 77 K.		
is observed, that is characteristic for systems with alternating magnetic and non-magnetic layers.