Strain-Tunable Spin Moment in Ni-Doped Graphene

TL;DR

This study demonstrates that applying uniaxial tensile strain to Ni-doped graphene induces and enhances its magnetic moment, enabling the design of strain-tunable spintronic devices.

Contribution

It reveals that uniaxial strain can induce a significant spin moment in Ni-doped graphene, which is non-magnetic in the relaxed state, showing a novel magnetoelastic effect.

Findings

Uniaxial strain induces a spin moment in Ni-doped graphene.

The spin moment increases with strain up to ~6.5%.

A transition to a high-spin state (~1.9 μ_B) occurs at critical strain.

Abstract

Graphene, due to its exceptional properties, is a promising material for nanotechnology applications. In this context, the ability to tune the properties of graphene-based materials and devices with the incorporation of defects and impurities can be of extraordinary importance. Here we investigate the effect of uniaxial tensile strain on the electronic and magnetic properties of graphene doped with substitutional Ni impurities (Ni_sub). We have found that, although Ni_sub defects are non-magnetic in the relaxed layer, uniaxial strain induces a spin moment in the system. The spin moment increases with the applied strain up to values of 0.3-0.4 \mu_B per Ni_sub, until a critical strain of ~6.5% is reached. At this point, a sharp transition to a high-spin state (~1.9 \mu_B) is observed. This magnetoelastic effect could be utilized to design strain-tunable spin devices based on Ni-doped graphene.