T. A. Len

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.

Magnetometric Studies of Catalyst Refuses in Nanocarbon Materials

It is shown that magnetometry can be employed as an effective tool to control the content of a ferromagnetic constituent in nanocarbon materials. We propose a thermochemical treatment protocol to achieve extensive cleaning of the source nanocarbon materials from ferromagnetic refuses.

Asymmetric magnetoresistance in the graphite intercalation compounds with cobalt

ABSTRACT The results of measurements of the magnetoresistance for graphite intercalation compounds with cobalt based on highly oriented pyrolytic graphite and fine crystalline pyrolytic graphite in the temperature range from 1.6 K to 293 K and in a magnetic field up to 16 T are presented. For the investigated intercalation compounds, the effect of asymmetry of the magnetoresistance relative to the magnetic field direction is revealed. It is shown that this effect can be satisfactorily explained within the Segal model of asymmetric magnetoresistance in thin films with large magnetic anisotropy.

Weak localization and interaction effects in acceptor graphite intercalation compounds

The presented work is devoted to investigations of manifestation of quantum effects of weak localization and interaction of charge carriers in electrical conductivity of acceptor graphite intercalation compounds (CICs). As shown by studies intercalation leads to a decrease in the resistivity and to change the resistivity temperature coefficient from negative sign in the source graphite on a positive sign in intercalated graphite. At the low temperature for all GICs specimens the minimum in the temperature dependence of resistivity is observed. In terms of the model of charge carriers weak localization and interaction for two-dimensional systems temperature dependence of phase relaxation time, localization radius and charge carriers screening constant for all GICs are estimated.

Semiconducting and Optical Properties of Compact Graphene-Like Nanoparticles of Molybdenum Disulfide

The research in the influence of graphene-like 2H-MoS2 nanoparticle structure on the behavior electroresistivity and optical properties has shown that the conductivity of semiconductor type (n-type) in the compact samples correlates with the particle sizes, in particular the size of 17–53 nm, along the basal plane [100] at a constant number of S–Mo–S nanolayers (n = 6–8) in graphene-like 2H-MoS2 nanoparticles. The mechanism of conductivity is supposed to be hopping conduction with variable hopping length for 2D case. The results of Raman studies indicate a significant impact of anisotropy sizes of 2H-MoS2 nanoparticles in direction [110] under constant number of nanolayers of S–Mo(W)–S on the formation of the structure-sensitive optical properties and, accordingly, the characteristics of the semiconductor as a whole.

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.