I. V. Ovsienko

Transport Properties of Composites with Carbon Nanotube‐Based Composites

Abstract The comparative investigation of structure, morphology, and transport properties of nanoscaled carbon materials (NCM) synthesized by different methods is carried out.

Resistance of a Nanocarbon Material Containing Nanotubes

The results of the experimental studies of resistivity of a nanocarbon material (NCM), which contains carbon nanotubes (CNT), and also the amorphous carbon particles and nanographite are presented. The main efforts were aimed at the ascertaining the mechanism of NCM conduction with regard to their phase composition.

Magnetoresistance of nanocarbon materials based on carbon nanotubes

The results of experimental investigations of magnetoresistance in nanocarbon material (NCM) containing carbon nanotubes in magnetic field up to 5 T and at temperature up to 0.54 K are reported. The obtained experimental magnetoresistance curves of NCM are described satisfactorily within the framework of the shrinkage effect of wave function of localized state in a magnetic field along with the spin-polarization mechanism.

Phonon Drag in GIC Based on Disordered Graphite

Abstract The work presents the results of investigation and calculation thermopower in GICs with SbCl5 based on disordered graphite.

Investigation of the thermoexfoliation process in different acceptor GICs

Abstract The studies of thermoexfoliation process in intercalation compounds Gr-SbCl5, Gr-ICI, and Gr-H2SO4 have shown that thermoexfoliation has a vivid non-linear threshold character. Experimental data are discussed within the thermodynamic theory of graphite intercalation compounds. Thermoexfoliation process takes place in the temperature range from T* to Tcr in which intercalant in GIC layers becomes unstable and the transition from the state “intercalant in GIC” into the state of pure intercalant occurs. The maximal effect of thermoexfoliation is obtained at high temperatures of thermal shock Te, i.e. at large heating rates of the sample.

Thermopower of Pregraphitic Carbons

Abstract The paper presents the results of investigations in thermoelectric power of pregraphitic carbons in the temperature range from 20 to 200K. The thermoelectric power of pregraphitic carbon has been shown to follow the model of sequential connection of islets with metallic conductivity, islets with hop conductivity of variable hop length and islets with hop conductivity of constant hop length. The description of thermoelectric power in islets of metallic conductivity requires the dependences of major mechanisms of charge carrier scattering on the temperature to be taken into account. The parameters of pregraphitic carbon electronic structure have been calculated from the experimental results on temperature dependence of electrical resistivity.

Investigations of Deintercalation Processes in Graphite Intercalation Compounds With SbCl5 and ICl

Results of the investigations of deintercalation process in intercalation compounds graphite-SbCl5 and graphite-ICl are presented. It was found that sample mass losses have a step character that testifies to the discrete transition from one stage of graphite intercalation compounds to another. The increase in the rate of heating breaks the step character of mass loss dependence on temperature and intensive mass losses occur without stage transitions.

ELECTROPHYSICAL PROPERTIES OF THE NANOCARBON MATERIALS

The model for describing the electrical conductivity of nanocarbon material, consisting of the particles of disordered carbon, carbon nanotubes and the ordered carbon phase is proposed.