Magnetism in graphite oxide: The role of epoxy groups

TL;DR

This study explores how epoxy groups on graphite oxide influence its magnetic properties, revealing that these groups induce magnetism which diminishes when they are destroyed, highlighting a novel magnetic behavior in oxidized graphite.

Contribution

It demonstrates that epoxy groups on graphite oxide surface are responsible for its magnetic properties, a previously unrecognized source of magnetism in graphite-based materials.

Findings

Magnetic susceptibility shows negative Curie temperature and slow relaxation.

Magnetic properties decrease after epoxy groups are destroyed.

Graphite oxide remains structurally intact while becoming insulating.

Abstract

We investigate the magnetism in graphite by controlled oxidation. Our approach renders graphite an insulator while maintaining its structure. Fourier transform infrared spectroscopy and X-ray absorption near edge structure spectra reveal that graphite oxide has epoxy groups on its surface and it is not thermally stable. Magnetic susceptibility data exhibit negative Curie temperature, field irreversibility, and slow relaxation. The magnetic properties diminish after the epoxy groups are destroyed. The overall results indicate the unexpected magnetism is associated with the presence of epoxy groups.