A new nanocluster carbyne-based material synthesized under high pressure

Demishev, S. V.; Pronin, A. A.; Sluchanko, N. E.; Samarin, N. A.; Ġlushkov, V. V.; Lyapin, A. G.; Kondrin, M. V.; Бражкин, В. В.; Varfolomeeva, T. D.; Попова, С. В.; Ohta, Hiromichi

doi:10.1134/1.1470537

Cited by 6 publications

(5 citation statements)

References 3 publications

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“…The detailed study of DC and AC conductivity and thermopower in hopping regime have been carried in [4][5][6] and confirmed above supposition. It was found [4][5][6] that quasi 1D hopping conductivity persists up to T syn ~ 700°C where the appearance of new sp 2 centers likely leads to the disorder and bending of individual chains in this range of synthesis temperatures. At T syn > 700°C, the increase in the fraction of the sp 2 bonds induces cross-linking between the chains, rendering the conduction two-dimensional.…”

Section: Introductionmentioning

confidence: 67%

“…This opens an intriguing opportunity of creation of an experimental system with variable dimensionality based on carbynes [4]. The detailed study of DC and AC conductivity and thermopower in hopping regime have been carried in [4][5][6] and confirmed above supposition. It was found [4][5][6] that quasi 1D hopping conductivity persists up to T syn ~ 700°C where the appearance of new sp 2 centers likely leads to the disorder and bending of individual chains in this range of synthesis temperatures.…”

Section: Introductionmentioning

confidence: 71%

“…The fraction of sp 2 bonds in carbyne and related sample resistivity ρ can be varied smoothly by applying high pressure and temperature [1]. An increase in the synthesis temperature T syn above 600 o C under pressure of 7 GPa allows to observe low temperature variable range hopping (VRH) transport for T < 40 K [1,[4][5][6]. It was found [4][5][6] that hopping exponent n in the Mott's law…”

Section: Introductionmentioning

confidence: 99%

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Hopping conductivity in carbynes. Magnetoresistance and Hall effect

Demishev

Pronin

Sluchanko

et al. 2003

phys. stat. sol. (c)

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In 2D and 3D carbyne samples synthesized under high pressure magnetoresistance and Hall effect have been studied in the region of variable range hopping conductivity T < 40 K. For both 2D and 3D cases magnetoresistance is positive, but analysis shows that shrinkage of the wave function in magnetic field does not allow describing experimental data quantitatively and anomalous contribution probably coming from quantum interference effects may be important. In 3D case Hall coefficient follows Mott's law similar to that observed in the temperature dependence of resistivity.

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Section: Introductionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

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Hopping conductivity in carbynes. Magnetoresistance and Hall effect

Demishev

Pronin

Sluchanko

et al. 2003

phys. stat. sol. (c)

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“…Note that, if the parent carbyne is a high-resistivity semiconductor [17], processing at 600-800 ° C sharply reduces its resistivity [17,18]. As shown by Demishev et al [21][22][23][24] in studies of the electrical and galvanomagnetic properties of carbynes modified by exposure to high temperatures and pressures, the low-temperature conduction in such materials is due to hopping transport. Increasing the processing temperature from 700 to 900 ° C leads to a transition from quasi-one-dimensional to three-dimensional hopping.…”

Section: Introductionmentioning

confidence: 99%

High-Pressure Structural Transformations of Carbyne

et al. 2005

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The structure of cumulenic carbyne samples is studied by x-ray diffraction after exposure to high temperatures and pressures (200-900 ° C, 7.7 GPa). The results indicate that, with increasing temperature, carbyne transforms from a highly disordered to x-ray amorphous state, with narrower diffuse bands. At high temperatures, a disordered graphite-like structure is formed, with a density substantially lower than that of graphite. The behavior of impurities during the structural transformation of carbyne is discussed.

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“…Publication [14] indicates that in order to make estimations in the one-dimensional case one can use coefficient t 2 = 1/360. Therefore, determining parameter T 0 from the measured temperature dependence ρ(T) and using the formula (2), one can calculate localization radius a.…”

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confidence: 99%

Electrophysical Properties of Onion-Like Carbon

et al. 2016

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The paper examines electrophysical properties of onion-like carbon (OLC) samples, where particles have the average size of 4-8 nm and are formed by 5-10 nested fullerene-like spheres connected by 1-3 common curved graphene shells into aggregates with a size of 50-300 nm. We measured the temperature dependence of electrical resistance from 4.2 to 300 K and dependence of magnetoresistance in magnetic fields up to 6 T at the temperature of 4.2 K. Temperature dependences of electrical resistance of samples can be described within the framework of the Mott law with variable hop length for the one-dimensional case or within the framework of the Efros-Shklovskii Coulomb gap. We observed the quadratically increasing positive magnetoresistance up to 6 T associated with compression of wave functions of conduction electrons. Negative magnetoresistance was observed in the range of magnetic fields up to 1-2 T in the case of some samples. This is due to the fact that magnetic field suppresses the contributions to magnetoresistance made by interference effects in the area of hopping conductivity. The measurements were used to estimate the localization radius that is comparable to the diameter of OLC particles (nano-onions).The prospects of new nanotechnologies are largely associated with the development of new materials based on carbon nanostructures (nanotubes, fullerenes, onion-like carbon, nano-graphene films). These carbon nano-objects possess extraordinary mechanical, electronic, emission, capillary, sorption and other properties compared to conventional carbon materials. Many applications in the field of coatings shielding electromagnetic radiation are available for carbon structures [1], composites with different carbon additives (graphites, soot, carbon fibers, carbon nanotubes [2][3][4][5][6], and carbon aerogels [7]). It was recently discovered that OLC and composite materials based thereon possess enhanced ability to absorb electromagnetic radiation in the wide range of wavelengths [8,9]. In order to understand the absorption processes, it is necessary to carefully examine electrophysical properties of such materials.The samples of onion-like carbon were synthesized by method of thermal annealing of different types of nanodiamonds at the temperature of 1800-2140 K in high vacuum [10]. One can divide the process of nano-diamond graphitization under these conditions into two stages. At the first stage, the least connected carbon atoms detach themselves from the surface of nano-diamond crystallites. This condition is met by carbon atoms located at the borders of diamond defects, as well as carbon atoms of the crystallographic plane (111). At the second stage, fullerene-like envelopes of OLC are formed from the graphene fragments. The process of graphitization starts from the surface of 1 A. V. Nikolaev

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A new nanocluster carbyne-based material synthesized under high pressure

Cited by 6 publications

References 3 publications

Hopping conductivity in carbynes. Magnetoresistance and Hall effect

Hopping conductivity in carbynes. Magnetoresistance and Hall effect

High-Pressure Structural Transformations of Carbyne

Electrophysical Properties of Onion-Like Carbon

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