Temperature dependent thermopower and resistance measurements of CNT-MgB2 composites

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Abstract

The temperature dependent resistance R(T) and thermopower S(T) of sintered single wall carbon nanotubes (SWCNT) and magnesium diboride (MgB2) composites containing 5wt%, 10wt%, and 15wt% of SWCNTs have been measured and compared to their pure counterparts. The thermopower of both MgB2 (in the normal state) and SWCNT remain positive over the entire temperature range (10K to 300K) with room temperature values being ∼ 8μV/K and 57μV/K, respectively. The thermopower of the sintered composites decreased with decreasing temperature and switched from positive to negative near 70K. The superconducting critical temperature (Tc) of the samples ranges from 38K-41K. The room-temperature resistance ratio (RRR) is seen to depend on the sample composition. The temperature width (ΔT) is observed to increase with increasing SWCNT concentration. The normal state resistance data were fitted with the generalized Block-Grüneisen function obtaining Debye temperature of ∼ 900K.

Original languageEnglish (US)
Title of host publicationCarbon Nanotubes, Graphene and Related Nanostructures
Pages123-128
Number of pages6
DOIs
Publication statusPublished - Dec 5 2012
Event2011 MRS Fall Meeting - Boston, MA, United States
Duration: Nov 28 2011Dec 2 2011

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1407
ISSN (Print)0272-9172

Other

Other2011 MRS Fall Meeting
CountryUnited States
CityBoston, MA
Period11/28/1112/2/11

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Adu, K. W., Jayasingha, R., Ma, D., & Sumanasekera, G. U. (2012). Temperature dependent thermopower and resistance measurements of CNT-MgB2 composites. In Carbon Nanotubes, Graphene and Related Nanostructures (pp. 123-128). (Materials Research Society Symposium Proceedings; Vol. 1407). https://doi.org/10.1557/opl.2012.705