THESIS
2016
xxiii, 133 pages : illustrations ; 30 cm
Abstract
This is an experimental study of the superconductivity of the carbon nanotubes
(CNTs) - more specifically the CNTs studied is 0.4 nm diameter single-wall CNTs
existing inside the channels of the AFI zeolite crystal, abbreviated as CNT@AFI
- by probing the magnetization property of this CNT@AFI system. These human
engineered 4-Angstrom CNTs, which is a nanoscale and low-dimensional
material, are approaching the limit set by nature, and superconductivity in the
CNTs in general is theoretically (microscopic or first-principles) both interesting
and challenging. Hence, empirical studies are important in providing useful
guiding information. The magnetization and specific-heat studies could provide
convincing evidences supporting or critiquing the electrical transport results of
th...[
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This is an experimental study of the superconductivity of the carbon nanotubes
(CNTs) - more specifically the CNTs studied is 0.4 nm diameter single-wall CNTs
existing inside the channels of the AFI zeolite crystal, abbreviated as CNT@AFI
- by probing the magnetization property of this CNT@AFI system. These human
engineered 4-Angstrom CNTs, which is a nanoscale and low-dimensional
material, are approaching the limit set by nature, and superconductivity in the
CNTs in general is theoretically (microscopic or first-principles) both interesting
and challenging. Hence, empirical studies are important in providing useful
guiding information. The magnetization and specific-heat studies could provide
convincing evidences supporting or critiquing the electrical transport results of
the CNT@AFI system. But probing the superconductivity in this system, as the
superconducting signal is very small in a large background, is another challenge.
Therefore the high-resolution calorimetry and magnetometry techniques detailed
in this thesis are invaluable.
With improved method of fabrication to increase the CNTs content inside the
channels of the AFI crystallites, the empirical results [Nanoscale 4, 21-41 (2012)]
were markedly different from those published in 2001 [Science 292, 2462 (2001)].
The magnetization results of this thesis largely agree with the results from the
electrical transport study [Phys. Rev. B 81, 174530 (2010)], but there is some
result that raises doubt in the critical current interpretation there. Lastly, there
is still some electrical transport result of this system that has not been explained
convincingly and is of interest.
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