Semimetallic and semiconductor properties of some superhard and ultrahard fullerites in the range 300-2 K
2000 (English)In: Proceedings of the 5th IUMRS International Conference on Advanced Materials, Beijing 1999, Elsevier B.V. , 2000, 1009-1015 p.Conference paper (Refereed)
Electrical resistivity and magnetoresistance were measured on samples with disordered structures synthesized from pure C60 and C70 at pressures in the range 8–12.5 GPa and temperatures of 900–1500 K. Different types of behaviour were observed: semimetallic, VRH and semiconducting, depending on the degree of disorder and the particular short-range order of the samples. A negative magnetoresistance was observed at T<10 K on samples with a semimetallic type of conductivity synthesized at 8 GPa pressure. The temperature dependence of resistivity in the sample with a disordered crystalline structure based on 3D-polymerized C60 molecules fits Mott's law for hopping conductivity. T3/2, T2 and T4 dependencies of conductivity are observed for samples with densities of 2.8 and 3.05 g/cm3 synthesized at a pressure of 12.5 GPa. The effect of hydrostatic pressure on the resistivity of cross-linked layered carbon structures obtained from C60 at P=8 GPa, T=1600 K was investigated up to 0.6 GPa at room temperature. An approximately linear decrease of resistivity was observed with a very small value of the derivative d ln ρ/dp=0.06 /GPa, which correlates with a very low compressibility of the material.
Place, publisher, year, edition, pages
Elsevier B.V. , 2000. 1009-1015 p.
, Journal of Physics and Chemistry of Solids, ISSN 0022-3697 ; 61, issue 7
Fullerenes, C60, high pressure synthesis, polymer, fullerene polymer, semimetal, semiconductor, variable range hopping, disorder, resistance, magnetoresistance, pressure dependence
Condensed Matter Physics
Research subject Physics
IdentifiersURN: urn:nbn:se:umu:diva-23079DOI: 10.1016/S0022-3697(99)00356-XOAI: oai:DiVA.org:umu-23079DiVA: diva2:219595
The 5th IUMRS International Conference on Advanced Materials, Beijing 1999
Editors: D. Zhu and Hans Kuzmany2009-05-282009-05-282013-02-04Bibliographically approved