Persistent currents and magnetic flux trapping in fragments of carbon deposits containing multiwalled nanotubes

TL;DR

This study investigates magnetic properties of carbon deposit fragments with multiwalled nanotubes, revealing persistent currents and flux trapping similar to superconductors, with flux decay observed at higher temperatures.

Contribution

It demonstrates magnetic flux trapping and persistent currents in carbon nanotube fragments, a phenomenon analogous to superconductivity, with detailed temperature-dependent flux relaxation behavior.

Findings

Magnetization curves show irreversible behavior indicating flux trapping.

Flux decay times are approximately 150 hours at 30K and 15 hours at room temperature.

Persistent currents are induced in the samples, akin to superconducting structures.

Abstract

It is found that the magnetization curves of samples of fragments of cathode carbon deposits with a high content of multiwalled nanotubes exhibit a pronounced irreversible character, attesting to the induction of persistent currents in the samples and to magnetic flux trapping, as happens in a multiply connected superconducting structure. A decrease of the trapped flux in time could not be observed at low (helium) temperatures with a measurement time of about 20 h. For intermediate (~30K) and room temperatures the trapped magnetic flux decays slowly with characteristic relaxation times of the order of 150 and 15 h, respectively.