Activation of magnetic moments in CVD-grown graphene by annealing

TL;DR

This study investigates how annealing at 300°C activates local magnetic moments in CVD-grown graphene, significantly affecting electron dephasing rates as measured by magnetoresistance, with effects influenced by gate voltage.

Contribution

It reveals that annealing induces magnetic moments in CVD graphene, altering dephasing behavior, a novel insight into graphene's magnetic properties after standard cleaning procedures.

Findings

Annealing increases dephasing rate beyond electron-electron interactions.

Magnetic moments are activated by annealing and depend on gate voltage.

Dephasing effects are significantly altered by annealing in inert gases.

Abstract

Effects of annealing on chemical vapor deposited graphene are investigated via a weak localization magnetoresistance measurement. Annealing at \SI{300}{\celsius} in inert gases, a common cleaning procedure for graphene devices, is found to raise the dephasing rate significantly above the rate from electron-electron interactions, which would otherwise be expected to dominate dephasing at 4 K and below. This extra dephasing is apparently induced by local magnetic moments activated by the annealing process, and depends strongly on the backgate voltage applied.