Meissner effect in honeycomb arrays of multi-walled carbon nanotubes

TL;DR

This paper reports the observation of the Meissner effect in honeycomb arrays of multi-walled carbon nanotubes, revealing superconductivity with a maximum Tc of 19 K and highlighting the role of intertube coupling and graphite structure.

Contribution

First demonstration of the Meissner effect in honeycomb arrays of multi-walled carbon nanotubes with a high Tc of 19 K, emphasizing the importance of array structure and intertube interactions.

Findings

Meissner effect observed in MWNT honeycomb arrays

Maximum Tc of 19 K among new-carbon superconductors

Intertube coupling and graphite structure are key factors

Abstract

We report Meissner effect for type-II superconductors with a maximum Tc of 19 K, which is the highest value among those in new-carbon related superconductors, found in the honeycomb arrays of multi-walled CNTs (MWNTs). Drastic reduction of ferromagnetic catalyst and efficient growth of MWNTs by deoxidization of catalyst make the finding possible. The weak magnetic anisotropy, superconductive coherence length (- 7 nm), and disappearance of the Meissner effect after dissolving array structure indicate that the graphite structure of an MWNT and those intertube coupling in the honeycomb array are dominant factors for the mechanism.