Stable Spin State Analysis of Fe, Co, Ni-modified Graphene-ribbon

TL;DR

This study uses first-principles DFT analysis to investigate the magnetic properties of Fe, Co, Ni-modified graphene ribbons, revealing stable spin states, magnetic moments, and potential applications in data storage and spintronic devices.

Contribution

It provides the first detailed analysis of stable spin states and electronic structures of transition metal-modified graphene ribbons, highlighting their potential for high-density data storage.

Findings

Fe-modified ribbon has Sz=4/2 as the most stable spin state.

Band structure shows half-metallic behavior with a large spin-dependent band gap.

Dual-layer Fe-modified ribbon suggests possible carbon nanotube formation.

Abstract

Magnetic graphene-ribbon is a candidate for realizing future ultra high density 100 tera bit/inch2 class data storage media. In order to increase the saturation magnetization, first principles DFT analysis was done for Fe, Co, Ni-modified zigzag edge graphene-ribbon. Typical unit cell is [C32H2Fe1], [C32H2Co1] and [C32H2Ni1] respectively. Most stable spin state was Sz=4/2 for Fe-modified case, whereas Sz=3/2 for Co-case and Sz=2/2 for Ni-case. Magnetic moment of Fe,Co, and Ni were 3.63, 2.49 and 1.26 {\mu}B, which can be explained by the Hund-rule considering charge donation to neighboring carbons. Band calculation shows half-metal like structure with a large band gap (in Co-case, 0.55eV) for up-spin, whereas very small gap (0.05eV) for down-spin, which will be useful for many featured application like information storage, spin filter and magneto-resistance devices. Dual layer Fe-modified ribbon shows a tube like curved structure, which may suggest a carbon nanotube creation by Fe catalyst.