摘要:

Nernst-Ettingshausen effect and longitudinal Nernst-Ettingshausen effect of the “NIKAFILM” and bromine-graphite compound were studied at applied magnetic field strength 1.4 (T). The Nernst-Ettingshausen coefficient of the bromine-graphite compound decreased 23% in comparison with that of pristine “NIKAFILM”. Similary the longitudinal Nernst-Ettingshausen effect was 54% smaller for the bromine-graphite compound in comparison with the “NIKAFILM”.

ISSN:1058-725X    

DOI:10.1080/10587250008025463

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Results of anin situconduction ESR (CESR) study of HNO3molecule intercalation into highly oriented pyrolytic graphite (HOPG) plate with width being comparable with the graphite skin-depth governed by c-axis conductivity are presented. The stepwise changes of the intensity of CESR signal from intercalated parts of the HOPG plate is clearly detected during the intercalation. Using the chemical potential vs. intercalation time offered by the authors for the experimental conditions, this dependence was calculated theoretically.

ISSN:1058-725X    

DOI:10.1080/10587250008025464

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Electrical conductivity and conduction ESR (CESR) of the second stage of graphite intercalation compound (GIC) with nitric acid (C10HNO3) in its incommensurate phase (210 K<T<250 K) are studied. Absence of the temperature dependence of the c-axis conductivity (σc) at preservation of the «« metallic »» temperature dependence of the conductivity along carbon layers (σa) is found. The analysis of the experimental data has shown that in the GIC studied the σc-conductivity realized by means of the non-band mechanism, as which one there can be mechanism of the transport of free charge carriers through the narrow high conductive paths (channels).

ISSN:1058-725X    

DOI:10.1080/10587250008025465

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The studies of thermoexfoliation process in intercalation compounds Gr-SbCl5, Gr-ICI, and Gr-H2SO4have 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 Tcrin 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.

ISSN:1058-725X    

DOI:10.1080/10587250008025466

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The equations that describe partial thermodynamic functions for graphite intercalation compounds (GIC) have been obtained. The derived equations determine the difference of chemical potentials between the intercalant in GIC layers and pure liquid intercalant in the first and the second order of approximation. The notion of T* temperature have been formulated, that determines the boundary of thermal stability of GIC. The formulated physical model of thermoexfoliation process of GIC is in agreement with experimental data.

ISSN:1058-725X    

DOI:10.1080/10587250008025467

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In order to optimise the thermal treatment of PPP at 700°C, we report on the electrochemical studies using solid polymer electrolytes composed of polyethylene oxide (PEO) and LiClO4of the insertion of lithium ions into PPP pyrolyzed at 700°C in argon atmosphere during increasing pyrolysis times (0.5; 1, 2 and 6 hours).

ISSN:1058-725X    

DOI:10.1080/10587250008025468

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Thec-axis resistivity ρc(H, T) of stage-4 MoCl5GIC between 1.9 and 50 K has been measured with and without an external magnetic field along the c axis (0≤H≤44 kOe). The interior G layers form a bottleneck to the c-axis conduction. The T and H dependence of ρcis mainly determined from that of the bottleneck resistivity proportional to the in-plane resistivity of interior graphite layers. A logarithmic behavior of ρcin the form of In(T) and In(H) indicates that the two-dimensional weak localization occurs in the interior graphite layers. The T and H dependence of the in-plane conductivity derived from ρcis discussed in terms of scaling relation predicted from the theory of two-dimensional weak localization.

ISSN:1058-725X    

DOI:10.1080/10587250008025469

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In pure pentacene film and iodine doped pentacene film, X-ray and electric conductivity measurements were performed. It was found from X-ray diffraction data that the iodine doped pentacene possess the stage-2 structure in addition to the stage-1 structure. The c axis lattice constant of the stage-2 structure, which is the length of the interval between the layers, was determined to be 33.2 Å. Moreover, electric conductivity was measured in pentacene doped with iodine at the various doping temperaturesTd. This result was compared with the results obtained from X-ray diffraction data.

ISSN:1058-725X    

DOI:10.1080/10587250008025470

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Potassium-phosphorus binaries are able to intercalate into graphite as potassium-oxygen or potassium-sulphur binaries, so that phosphorus behave as a classical electronegative element. But, it is able, on the other hand, to behave as a metal such as mercury, so that potassium-phosphorus and potassium-mercury binaries intercalate into graphite by very close synthesis routes. Phosphorus appears thus as a linking element between strongly and fairly electronegative species.

ISSN:1058-725X    

DOI:10.1080/10587250008025471

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

U-graphite intercalation compound (GIC) was prepared in-situ by deposition of U metal onto single-crystalline graphite(0001) and subsequent annealing. The samples were studied by angle-resolved photoemission (PE) and resonant PE at the 5d→ 5f excitation threshold. From a comparison of the experimental data with results of our LDA-LCAO calculations, the electronic structure of the GIC may be understood in a first approach by a charge transfer from the U atoms to unoccupied π0* orbitals of graphite. The latter is related to a shift to higher binding energies of all graphite-derived PE features and appearance of an additional rather narrow feature at the Fermi energy upon intercalation. This Fermi-level peak is superimposed by a sharp U 5fsignal, that reveals no trace of multiplet splitting. Since our results give clear evidence for a localized character of the U 5fstates, we assume that U is mixed-valent in this compound.

ISSN:1058-725X    

DOI:10.1080/10587250008025472

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor