It has been claimed that graphite hosts superconductivity at room temperature, although all efforts to isolate it have been vain. Here we report a separation method that uses magnetic field gradients to sort the superconducting from normal grains out of industrial graphite powders. We have obtained a concentrate of above room temperature superconducting particles. Electrical resistance measurements on agglomerates of sorted grains of three types of graphite show transition temperatures up to Tconset∼ 700K with zero resistance up to ∼ 500K. Magnetization measurements confirm these values through jumps at \textit{Tc} in the zero field cooled curves, and by the occurrence diamagnetic hysteretic cycles shrinking with temperature. Our results open the door towards the study of above room temperature superconducting ill-stacked graphite phases.
@article{arxiv.2410.18020,
title = {Magnetic field sorting of superconducting graphite particles with T$_c$$>$400K},
author = {Manuel Núñez-Regueiro and Thibaut Devillers and Eric Beaugnon and Armand de Marles and Thierry Crozes and Sébastien Pairis and Christopher Swale and Holger Klein and Olivier Leynaud and Abdelali Hadj-Azzem and Frédéric Gay and Didier Dufeu},
journal= {arXiv preprint arXiv:2410.18020},
year = {2024}
}