Magnetism and Superconductivity in Hydrogenated Graphite Foils

TL;DR

This paper reports the coexistence of magnetism and superconductivity in hydrogenated graphite foils, revealing multiple magnetic transitions and high-temperature superconductivity up to 60 K, highlighting the role of magnetism in electronic correlations.

Contribution

It presents new experimental evidence of magnetic and superconducting phases coexisting in hydrogenated graphite foils, expanding understanding of unconventional superconductors.

Findings

Ferromagnetism observed up to room temperature.

Superconductivity with critical temperature 50-60 K.

Multiple magnetic phase transitions with increasing magnetic field.

Abstract

Unique to certain unconventional superconductors is the coexistence of magnetism and superconductivity. We have previously found ferromagnetism and superconductivity in hydrogenated graphitic materials. Herein we present similar as well as completely new findings this time applicable to hydrogenated graphite foils. As the strength of the magnetic field is increased, the temperature-dependent magnetization shows several important transitions. From a Neel paramagnetic-antiferromagnetic transition, to a ferromagnetic superconductor state, to an orbital paramagnetic glass high-temperature superconductor with critical temperature for the dominant phase at Tc = 50 to 60 K. The ferromagnetic state is observed up to room temperature. Thus, the magnetism of hydrogenated low-density carbon graphite foils plays an important role in establishing electronic correlations of which some are superconducting in nature.