N. A. Vinnikov

Publications (12)1.35 Total impact

• Article: The effect of the glass transition in fullerite C60 on Ar impurity diffusion

  A. V. Dolbin, V. B. Esel'son, V. G. Gavrilko, V. G. Manzhelii, N. A. Vinnikov, R. M. Basnukaeva
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  ABSTRACT: The kinetics of sorption and subsequent desorption of argon gas by a C60 powder has been investigated in the temperature interval 58-290 K. The temperature dependence of the coefficients of Ar diffusion in fullerite has been obtained using the measured characteristic times of sorption. The diffusion coefficients of Ar decrease monotonically with lowering temperature in the whole range of the investigated temperatures, which corresponds to the thermally activated diffusion of Ar atoms in fullerite. The glass transition in fullerite induces an order-of-magnitude decrease in the activation energy of Ar diffusion in fullerite. Most likely this is because new directions may appear due to the glass transition in which the barriers separating the interstitial voids in the C60 lattice are significantly lower
  11/2012;
• Article: Kinetics of the sorption of 3He by C60 fullerite. The quantum diffusion of 3He and 4He in fullerite

  A. V. Dolbin, V. B. Esel’son, V. G. Gavrilko, V. G. Manzhelii, N. A. Vinnikov, S. N. Popov
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  ABSTRACT: The kinetics of the sorption and subsequent desorption of gaseous 3He in a C60 fullerite powder has been studied in the temperature range of 2–292 K. The temperature dependences of the diffusion coefficients of 3He and 4He impurities in fullerite have been plotted using the measured characteristic times of filling of octahedral and tetrahedral interstices, as well as previous data. These temperature dependences of the diffusion coefficients of 3He and 4He impurities in fullerite are qualitatively similar. A decrease in the temperature from 292 to 79 K is accompanied by a decrease in the diffusion coefficients, which corresponds to the dominance of the thermally activated diffusion of helium isotopes in fullerite. A further decrease in the temperature to 8–10 K leads to an increase in the diffusion coefficients by more than an order of magnitude. The diffusion coefficients of 3He and 4He are independent of the temperature below 8 K, indicating the tunnel character of the diffusion of helium in C60 fullerite. The isotope effect is manifested in the difference between the absolute values of the diffusion coefficients of 3He and 4He atoms at the same temperatures.
  JETP Letters 05/2012; 93(10):577-579. · 1.35 Impact Factor
• Source

  Available from: Alexander Dolbin

  Article: The effect of O2 impurities on the low temperature radial thermal expansion of bundles of closed single-walled carbon nanotubes

  A. V. Dolbin, V. B. Esel'son, V. G. Gavrilko, V. G. Manzhelii, S. N. Popov, N. A. Vinnikov, B. Sundqvist
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  ABSTRACT: The effect of oxygen impurities upon the radial thermal expansion (ar) of bundles of closed single-walled carbon nanotubes has been investigated in the temperature interval 2.2-48 K by the dilatometric method. Saturation of bundles of nanotubes with oxygen caused an increase in the positive ar-values in the whole interval of temperatures used. Also, several peaks appeared in the temperature dependence ar(T) above 20 K. The low temperature desorption of oxygen from powders consisting of bundles of single-walled nanotubes with open and closed ends has been investigated
  07/2011;
• Source

  Available from: Alexander Dolbin

  Article: Quantum phenomena in the radial thermal expansion of bundles of single-walled carbon nanotubes doped with 3He. A giant isotope effect

  A. V. Dolbin, V. B. Esel'son, V. G. Gavrilko, V. G. Manzhelii, N. A. Vinnikov, S. N. Popov, B. Sudqvist
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  ABSTRACT: The radial thermal expansion {\alpha}r of bundles of single-walled carbon nanotubes saturated with 3He up to the molar concentration 9.4% has been investigated in the temperature interval 2.1-9.5 K by high-sensitivity capacitance dilatometry. In the interval 2.1-7 K a negative {\alpha}r was observed, with a magnitude which exceeded the largest negative {\alpha}r values of pure and 4He-saturated nanotubes by three and two orders of magnitude, respectively. The contributions of the two He isotope impurities to the negative thermal expansion of the nanotube bundles are most likely connected with the spatial redistribution of 4He and 3He atoms by tunneling at the surface and inside nanotube bundles. The isotope effect turned out to be huge, probably owing to the higher tunneling probability of 3He atoms.
  02/2011;
• Source

  Available from: Alexander Dolbin

  Article: Kinetics of 4He gas sorption by fullerite C60. Quantum effects

  A. V. Dolbin, V. B. Esel'son, V. G. Gavrilko, V. G. Manzhelii, N. A. Vinnikov, S. N. Popov
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  ABSTRACT: The kinetics of helium gas sorption by a C60 powder and subsequent desorption of the 4He impurity from the saturated powder has been investigated in the temperature interval T = 2-292 K. Evidence is obtained that supports the existence of two stages in the temperature dependences of sorption and desorption. The stages account for the different times taken by helium to occupy the octahedral and tetrahedral interstices in the C60 lattice. The characteristic times of sorption and desorption coincide. It is found that the temperature dependences of the characteristic times of occupying the octahedral and tetrahedral interstices are nonmonotonic. As the temperature is lowered from 292 K to 79.3 K, the characteristic times increase, which indicates a predominance of thermally activated diffusion of helium in C60. On a further decrease to T = 10 K the characteristic times reduce over an order of magnitude. Below 8 K the characteristic times of sorption and desorption are temperature-independent. This suggests a tunnel character of 4He diffusion in C60.
  08/2010;
• Source

  Available from: Alexander Dolbin

  Article: Quantum effects in the radial thermal expansion of bundles of single-walled carbon nanotubes doped with 4He

  A. V. Dolbin, V. B. Esel'son, V. G. Gavrilko, V. G. Manzhelii, S. N. Popov, N. A. Vinnikov, B. Sundqvist
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  ABSTRACT: The radial thermal expansion (ar) of bundles of single-walled carbon nanotubes saturated with 4He impurities to the molar concentration 9.4% has been investigated in the interval 2.5-9.5 K using the dilatometric method. In the interval 2.1-3.7 K (ar) is negative and is several times higher than the negative (ar) for pure nanotube bundles. This most likely points to 4He atom tunneling between different positions in the nanotube bundle system. The excess expansion was reduced with decreasing 4He concentration. Comment: 4 pages, 1 figure, will be published in Fiz.Nizk Temp. #7, 2010
  04/2010;
• Source

  Available from: Alexander Dolbin

  Article: The low temperature thermal expansion of single-walled carbon nanotube bundles saturated with nitrogen

  A. V. Dolbin, V. B. Esel'son, V. G. Gavrilko, V. G. Manzhelii, S. N. Popov, N. A. Vinnikov, B. Sundqvist
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  ABSTRACT: The effect of a N2 impurity on the radial thermal expansion coefficient (ar) of single-walled carbon nanotube bundles has been investigated in the temperature interval 2.2 - 43 K by the dilatometric method. Saturation of nanotube bundles with N2 caused a sharp increase in the positive magnitudes of ar in the whole range of temperatures used and a very high and wide maximum in the thermal expansion coefficient (ar)(T) at T about 28 K. The low temperature desorption of the impurity from the N2-saturated powder of bundles of single-walled carbon nanotubes with open and closed ends has been investigated. Comment: 10 pages, 5 figures, will be published in Fiz.Nizk Temp. #5, 2009
  01/2010;
• Source

  Available from: Alexander Dolbin

  Article: The effect of sorbed hydrogen on low temperature radial thermal expansion of single walled carbon nanotube bundles

  A. V. Dolbin, V. B. Esel'son, V. G. Gavrilko, V. G. Manzhelii, S. N. Popov, N. A. Vinnikov, B. Sundqvist
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  ABSTRACT: The effect of a normal H2 impurity upon the radial thermal expansion (Ar) of SWNT bundles has been investigated in the interval T = 2.2-27 K using the dilatometric method. It is found that H2 saturation of SWNT bundles causes a shift of the temperature interval of the negative thermal expansion towards lower (as compared to pure CNTs) temperatures and a sharp increase in the magnitude of (Ar) in the whole range of temperatures investigated. The low temperature desorption of H2 from a powder consisting of bundles of SWNTs, open and closed at the ends, has been investigated. Comment: 10 pages, 2 figures
  07/2009;
• Source

  Available from: Alexander Dolbin

  Article: Radial thermal expansion of pure and Xe-saturated bundles of single-walled carbon nanotubes at low temperatures

  A. V. Dolbin, V. B. Esel'son, V. G. Gavrilko, V. G. Manzhelii, S. N. Popov, N. A. Vinnikov, N. I. Danilenko, B. Sundqvist
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  ABSTRACT: The radial thermal expansion coefficient (a)r of pure and Xe-saturated bundles of single-walled carbon nanotubes has been measured in the interval 2.2-120 K. The coefficient is positive above T = 5.5 K and negative at lower temperatures. The experiment was made using a low temperature capacitance dilatometer with a sensitivity of 2x10-9 cm and the sample was prepared by compacting a CNT powder such that the pressure applied oriented the nanotube axes perpendicular to the axis of the cylindrical sample. The data show that individual nanotubes have a negative thermal expansion while the solid compacted material has a positive expansion coefficient due to expansion of the intertube volume in the bundles. Doping the nanotubes with Xe caused a sharp increase in the magnitude of (a)r in the whole range of temperatures used, and a peak in the dependence (a)r (T) in the interval 50-65 K. A subsequent decrease in the Xe concentration lowered the peak considerably but had little effect on the thermal expansion coefficient of the sample outside the region of the peak. The features revealed have been explained qualitatively. Comment: 12 pages,6 figures
  02/2009;
• Source

  Available from: Alexander Dolbin

  Article: Radial thermal expansion of single-walled carbon nanotube bundles at low temperatures

  A. V. Dolbin, V. B. Esel'son, V. G. Gavrilko, V. G. Manzhelii, N. A. Vinnikov, S. N. Popov, B. Sundqvist
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  ABSTRACT: The linear coefficient of the radial thermal expansion has been measured on a system of SWNT bundles in an interval of 2.2 - 120K. The measurement was performed using a dilatometer with a sensitivity of 2*10-9 cm. The cylindrical sample 7 mm high and 10 mm in diameter was obtained by compressing powder. The resulting bundles of the nanotubes were oriented perpendicular to the sample axis. The starting powder contained over 90% of SWNTs with the outer diameter 1.1 nm, the length varying within 5-30 um. Comment: 4 pages, 1 figure
  06/2008;
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  Available from: Alexander Dolbin

  Article: The effect of the noncentral impurity-matrix interaction upon the thermal expansion and polyamorphism of solid CO-C60 solutions at low temperatures

  A. V. Dolbin, V. B. Esel'son, V. G. Gavrilko, V. G. Manzhelii, N. A. Vinnikov, G. E. Gadd, S. Moricca, D. Cassidy, B. Sundqvist
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  ABSTRACT: Orientational glasses with CO molecules occupying 26% and 90% of the octahedral interstitial sites in the C60 lattice have been investigated by the dilatometric method in a temperature interval of 2.5 - 23 K. At temperatures 4 - 6 K the glasses undergo a first-order phase transition which is evident from the hysteresis of the thermal expansion and the maxima in the temperature dependences of the linear thermal expansion coefficients, and the thermalization times of the samples. The effect of the noncentral CO-C60 interaction upon the thermal expansion and the phase transition in these glasses was clarified by comparing the behavior of the properties of the CO-C60 and N2-C60 solutions. Comment: 11 pages, 7 figures
  03/2008;
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  Available from: Alexander Dolbin

  Article: Specific features of thermal expansion and polyamorphism in CH–C solutions at low temperatures

  A V Dolbin, V B Esel 'son, V G Gavrilko, V G Manzhelii, N A Vinnikov, G E Gadd, S Moricca, D Cassidy, B Sundqvist
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  ABSTRACT: The temperature dependence of the linear thermal expansion coefficient a(T) has been investigated in the temperature range of 2.5 to 23 K for two different CH 4 –C 60 solutions in which CH 4 molecules occupied 24 and 50% of the octahedral interstitial sites of the C 60 lattice. In both cases, a(T) exhibits hysteresis, sug-gesting the existence of two types of orientational glass associated with these solutions. The temperature of the first-order phase transition between these two glasses was estimated and the behavior of these two glasses compared. The characteristic times of thermalization t 1 , reorientation of the C 60 molecules t 2 , and of the phase transformation between the glasses t¢, have been estimated for these solutions. Both the temper-ature dependence of a(T) and the characteristic thermalization time t 1 are found to have features near the phase transition temperature and an explanation has been put forward to explain these observed features. PACS: 74.70.Wz Fullerenes and related materials.
  01/2007; 33:1401-1405.