Irradiation Enhanced paramagnetism on graphene nanoflakes

TL;DR

This study investigates how nitrogen ion irradiation affects the paramagnetism of graphene nanoflakes, revealing increased magnetization at low doses and reduction at higher doses due to amorphization, with no ferromagnetism observed.

Contribution

It provides new insights into the dose-dependent magnetic behavior of irradiated graphene nanoflakes and the effects of ion-induced amorphization on their magnetic properties.

Findings

Paramagnetism increases at low irradiation doses.

Higher doses lead to amorphization and reduced magnetization.

No ferromagnetism observed down to 5K.

Abstract

We have studied the magnetization of vertically aligned graphene nanoflakes irradiated with nitrogen ions of 100 KeV energy and doses in the range 10^11- 10^17 ions/cm2. The non-irradiated graphene nanoflakes show a paramagnetic contribution, which is increased progressively by ion irradiation at low doses up to 10^15 /cm^2. However, further increase on implantation dose reduces the magnetic moment which coincides with the onset of amorphization as verified by both Raman and X-ray photoelectron spectroscopic data. Overall, our results demonstrate the absence of ferromagnetism on either implanted or unimplanted samples from room temperature down to a temperature of 5K