Superconducting resistive transition in coupled arrays of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mn>4</mml:mn><mml:mspace width="0.2em" /><mml:mtext>Å</mml:mtext></mml:mrow></mml:math>carbon nanotubes

Wang, Zhe; Shi, Wu; Xie, Hang; Zhang, Ting; Wang, Ning; Tang, Zikang; Zhang, Xixiang; Lortz, Rolf; Sheng, Ping; Sheikin, I.; Demuer, A.

doi:10.1103/physrevb.81.174530

Cited by 36 publications

(93 citation statements)

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“…Superconducting correlations are present up to a much higher field of 28 Tesla. 20 The specific heat anomaly seen in Fig. 21 most likely represents only a part of the total superconducting specific-heat signal, related to a growing superconducting condensate competing with a decreasing correlation length as the temperature is lowered.…”

Section: Thermal Specific Heat Characteristicsmentioning

confidence: 99%

“…As the array becomes larger, the energy separation between the Peierls distortion/CDW state and the superconducting ground state would increase, thereby facilitating an eventual transition to the 3D superconducting state as mediated by a Berezinskii-Kosterlitz-Thouless (BKT) transition in the ab plane perpendicular to the c-axis of the nanotubes. 20 Such a crossover transition is the subject matter of the following section.…”

Section: Quasi One Dimensional Fluctuation Superconductivitymentioning

confidence: 99%

“…A sharp drop is seen to initiate at 7.5 K, and this drop is moved to lower temperatures with increasing magnetic fields, applied perpendicular to the c-axis. 20 The fact that a magnetic field can affect the transition temperature means that the superconductivity originates from coupled carbon nanotube arrays which must extend at least a few tens of nanometres in the transverse dimension. The inset of Fig.…”

Section: Crossover From Quasi One Dimensional To Three Dimensional Sumentioning

confidence: 99%

“…In the following we describe the procedure of device fabrication to make four electrodes on the sample with a separation between the two surface electrodes being $100 nm. 20 The AFI crystals are first heated in 300 mbar of oxygen and 700 mbar N 2 at 580 C for 4 hours, to remove the TPA inside the channels. A selected crystal is picked out and glued on a silicon wafer.…”

Section: Device Fabrication and Measurement Geometrymentioning

confidence: 99%

“…Other than the above-stated reasons, this is because only three groups have observed superconductivity in carbon nanotubes, 15,17,18 and even for these three groups no consistent sets of data, which should comprise electrical, magnetic, and thermal specific heat measurements, were obtained until recently. [19][20][21] This review serves to gather all the experimental evidence for superconductivity in one type of carbon nanotube-the 4-Angstrom single-walled carbon nanotubes (SWNTs) embedded in AlPO 4 -5 zeolite template. The experimental data offer some answers to how the superconductivity can appear in spite of the various above-stated obstacles.…”

Section: Introductionmentioning

confidence: 99%

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Superconductivity in 4-Angstrom carbon nanotubes—a short review

et al. 2012

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We give an up-to-date review of the superconducting phenomena in 4-Angstrom carbon nanotubes embedded in aligned linear pores of the AlPO 4 -5 (AFI) zeolite, first discovered in 2001 as a fluctuation Meissner effect. With the introduction of a new approach to sample synthesis around 2007, new data confirming the superconductivity have been obtained. These comprise electrical, specific heat, and magnetic measurements which together yield a consistent yet complex physical picture of the superconducting state, largely owing to the one-dimensional (1D) nature of the 4-Angstrom carbon nanotubes. For the electrical transport characteristics, two types of superconducting resistive behaviors were reproducibly observed in different samples. The first type is the quasi 1D fluctuation superconductivity that exhibits a smooth resistance drop with decreasing temperature, initiating at 15 K. At low temperatures the differential resistance also shows a smooth increase with increasing bias current (voltage). Both are unaffected by an applied magnetic field up to 11 Tesla. These manifestations are shown to be consistent with those of a quasi 1D superconductor with thermally activated phase slips as predicted by the Langer-Ambegaokar-McCumber-Halperin (LAMH) theory. The second type is the quasi 1D to 3D superconducting crossover transition, which was observed to initiate at 15 K with a slow resistance decrease switching to a sharp order of magnitude drop at $7.5 K. The latter exhibits anisotropic magnetic field dependence and is attributed to a Berezinskii-Kosterlitz-Thouless (BKT)-like transition that establishes quasi-long-range order in the plane transverse to the c-axis of the aligned nanotubes, thereby mediating a 1D to 3D crossover. The electrical data are complemented by magnetic and thermal specific heat bulk measurements. By using both the SQUID VSM and the magnetic torque technique, the onset of diamagnetism was observed to occur at $15 K, with a rapid increase of the diamagnetic moment below $7 K. The zero-field-cooled and field-cooled branches deviated from each other below 7 K, indicating the establishment of a 3D Meissner state with macroscopic phase coherence. The superconductivity is further supported by the specific heat measurements, which show an anomaly with onset at 15 K and a peak at 11-12 K. In the 3D superconducting state, the nanotube arrays constitute a type-II anisotropic superconductor with H c1 z 60 to 150 Oe, coherence length x z 5 to 15 nm, London penetration length l z 1.5 mm, and Ginzburg-Landau k z 100. We give a physical interpretation to the observed phenomena and note the challenges and prospects ahead.

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Section: Thermal Specific Heat Characteristicsmentioning

confidence: 99%

Section: Quasi One Dimensional Fluctuation Superconductivitymentioning

confidence: 99%

Section: Crossover From Quasi One Dimensional To Three Dimensional Sumentioning

confidence: 99%

Section: Device Fabrication and Measurement Geometrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Superconductivity in 4-Angstrom carbon nanotubes—a short review

et al. 2012

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1D Superconductivity in a Related System

Altomare

Chang

2013

One‐Dimensional Superconductivity in Nanowires

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Thermal stability and flammability of ethylene vinyl acetate copolymers in presence of nanoclay and a halogen‐free flame retardant

Entezam

Khonakdar

Jafari

et al. 2016

Vinyl Additive Technology

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In this study, thermal stability behavior and flammability of ethylene-vinyl-acetate (EVA) copolymers containing organo-modified nanoclay particles (Cloisite 15A) and ammonium polyphosphate (APP) along with pentaerythritol (PER), as halogen-free flame retardants, were investigated. Transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) were employed for evaluation of the level of dispersion of nanosheets within the EVA matrix. Moreover, thermal stability behavior and flammability of the samples were studied using thermogravimetric analysis (TGA), cone calorimetry thermometer (CCT) and limiting oxygen index (LOI). The obtained results from TEM and SAXS showed that nanosheets exhibited a rather proper level of dispersion within the EVA matrix. According to TGA and CCT results, despite improving the thermal stability and flame retardancy of EVA due to incorporation of the individual additives, a considerable synergistic effect was observed upon simultaneous use of clay nanosheets and the flame retardants. Such synergistic effect was explained by the physical mechanism of the solid phase due to the increased residual ash resulted from combustion of the samples containing flame retardants and clay nanosheets. While clay nanosheets had no significant effect on the LOI of EVA, the halogen-free flame retardants substantially increased the LOI of EVA. J. VINYL ADDIT. TECHNOL., 23:E92-E98, 2017.

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Superconducting resistive transition in coupled arrays of4Åcarbon nanotubes

Cited by 36 publications

References 50 publications

Superconductivity in 4-Angstrom carbon nanotubes—a short review

Superconductivity in 4-Angstrom carbon nanotubes—a short review

1D Superconductivity in a Related System

Thermal stability and flammability of ethylene vinyl acetate copolymers in presence of nanoclay and a halogen‐free flame retardant

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