We report on electrical resistance measurements of an individual carbon nanotube down to a temperature $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}20\mathrm{mK}$. The conductance exhibits $\mathrm{ln}T$ dependence and saturates at low temperature. A magnetic field applied perpendicular the tube axis increases produces aperiodic fluctuations. data find global coherent interpretation in terms two-dimensional weak localization universal fluctuations mesoscopic conductors....

Measurements of the low field galvanomagnetic tensor components bismuth from 77 to 300K are reported. The eight magnetoresistivity coefficients Aij found vary as T-2 up nearly 120 K, then T-3.9 300 K. electronic parameters computed. values electron ellipsoid tilt angle lie between 6 degrees 40' and 8 30' carrier density varies 4.55*1017 24.5*1017 cm-3 at K respectively. All mobilities except mu 2 in lowest temperature range.

Techniques are presented for making ohmic contacts to nanowires with a thick oxide coating. Although experiments were carried out on Bi nanowires, the techniques described in this paper generally applicable other nanowire systems. Metal electrodes patterned individual using electron beam lithography. Imaging chemical reaction atomic scale situ high-resolution transmission microscopy shows that annealing H2 or NH3 can reduce nanowires' coating completely. The high temperatures required...

After the early work of Steele and Babiskin, low-temperature transport properties in bismuth at high magnetic fields have been used to investigate band structure, only periods quantum oscillations were interest. In this paper, both amplitude magnitude monotonic components (magnetoresistance, Hall, magneto-Seebeck, Nernst) are investigated liquid-helium range, where phonon drag dominates zero-field properties. Measurements extended regime a few electron levels occupied. Experimental results...

The weak-localization phenomenon for two-dimensional (2D) electronic systems is invoked to explain the negative magnetoresistance as well low-temperature dependence of resistivity pyrocarbon samples heat treated between 2000 and 2600 \ifmmode^\circ\else\textdegree\fi{}C. 2D character found originate from random stacking graphene layers (turbostratic structure) characteristic pregraphitic carbon materials. For a heat-treatment temperature (HTT) lower than 2200...

High-resolution resistivity and magnetoresistance measurements have been performed as a function of temperature on pregraphitic carbon fibers. The exhibits negative coefficient (d\ensuremath{\rho}/dT<0) from room down to 1.5 K. It is shown that such behavior can hardly be explained by thermal excitation carriers in the liquid-helium range within framework simple two-band model, usually applied graphitic structures. present component more pronounced at low temperature. found magnetic field...

The stage and temperature dependences of the in-plane thermal conductivity graphite-Fe${\mathrm{Cl}}_{3}$ acceptor intercalation compounds are reported analyzed, as well dependence a stage-5 potassium donor compound. measured is tentatively separated into an electronic contribution, which dominant at low temperatures, lattice around room temperature. Quantitative information provided about defects introduced by scatter both electrons phonons. Below reduced order magnitude relative to...

The physical properties of carbon-boron nitride (C-BN) prepared from mixtures BCl3, NH3, and selected hydrocarbons by codeposition methods have been investigated using x-ray diffraction, electron transmission spectroscopy, photoelectron Raman scattering, optical reflectivity, thermal conductivity, thermopower, electrical resistivity. Taken collectively, the results these experiments indicate that compression-annealed C-BN materials studied here consist separated domains pyrolytic boronated...

Polypropylene-based composites filled with carbon fibers and multiwall nanotubes were produced by coagulation precipitation technique. Composite articles conventional injection molding It was shown that the addition of (10% total amount fibers) results in significantly increased anisotropic thermal conductivity composite due to formation conductive bridges between fibers, which are oriented during molding. The CNTs has a significant effect more than 50–70% increase both axial transverse...

The temperature variation of the thermal conductivity six samples pitch-derived carbon fibers has been measured in range 3T300 K. lattice fitted, with boundary and point-defect scattering for phonons taken into consideration. It is shown that in-plane coherence lengths determined by x-ray diffraction are almost equal to phonon mean free paths scattering. thus suggested thermal-conductivity measurements can be used determine quantitatively where techniques inadequate. analysis also allows one...

We report measurements on the electrical- and thermal-transport properties of fluorine-intercalated vapor-grown carbon fibers ${\mathrm{C}}_{\mathit{x}}$F with carbon-to-fluorine-atom ratio x between 4.1 5.8. The electrical resistivity is found to be very sensitive fluorine concentration. Indeed, while resistivities ${\mathrm{C}}_{5.2}$F ${\mathrm{C}}_{5.8}$F compounds are well below that pristine graphite fibers, tendency reversed when x\ensuremath{\le}4.5 large values obtained. All exhibit...

This paper reports on the preparation and characterization of structural, electrical thermoelectric properties nanocomposite films formed from three-dimensional networks polycrystalline bismuth (Bi) nanowires (NWs). The samples were fabricated by electrodeposition within polycarbonate (PC) templates with crossed cylindrical nanopores, yielding self-supported Bi (CNWs) mean diameter values ranging 23 nm to 230 nm. Temperature changes in resistance thermopower studied considering electric...