Spin-half paramagnetism in graphene induced by point defects

TL;DR

This study demonstrates that point defects such as fluorine adatoms and vacancies induce spin-1/2 paramagnetism in graphene, significantly affecting its magnetic properties without leading to magnetic ordering at very low temperatures.

Contribution

It provides experimental evidence that specific point defects in graphene induce paramagnetism with spin 1/2, highlighting the effects of defect clustering and structural stability.

Findings

Defects induce measurable paramagnetism in graphene.

No magnetic ordering observed down to liquid helium temperatures.

Maximum magnetic response limited by defect clustering and structural stability.

Abstract

Using magnetization measurements, we show that point defects in graphene - fluorine adatoms and irradiation defects (vacancies) - carry magnetic moments with spin 1/2. Both types of defects lead to notable paramagnetism but no magnetic ordering could be detected down to liquid helium temperatures. The induced paramagnetism dominates graphene's low-temperature magnetic properties despite the fact that maximum response we could achieve was limited to one moment per approximately 1000 carbon atoms. This limitation is explained by clustering of adatoms and, for the case of vacancies, by losing graphene's structural stability.