Giant magnetoresistance in bilayer graphene nanoflakes

Abstract

Coherent spin transport through bilayer graphene (BLG) nanoflakes sandwiched between two electrodes made of single-layer zigzag graphene nanoribbon was investigated by means of Landauer-Buttiker formalism. Application of a magnetic field only on BLG structure as a channel produces a perfect spin polarization in a large energy region. Moreover, the conductance could be strongly modulated by magnetization of the zigzag edge of AB-stacked BLG, and the junction, entirely made of carbon, produces a giant magnetoresistance (GMR) up to 10 6 %. Intestinally, GMR and spin polarization could be tuned by varying BLG width and length. Generally, MR in a AB-stacked BLG strongly increases (decreases) with length (width).

Spin photocurrents in chevron-type graphene nanoribbons under terahertz to visible light irradiation

“…In other words, the designed spin-photovoltaic device produces a spin photocurrent with a quantum efficiency up to ≈52%, and a spin polarization with a maximum value of more than 90% under the investigated photon energies. Furthermore, we found the possibility of an optically induced MR more than 3000%, which is comparable to, or better than, the typical MR and optically induced MR values of GNRs reported in the literature [10,15,41,42]. On the other hand, when the irradiated light is circularly polarized, our designed nanodevice could act as helicity detector, which is due to the optical orientation process, and also reveals an optically induced MR with a maximum value more than 3800%.…”

Ferrimagnetic and antiferromagnetic phase in bilayer graphene nanoflake controlled with external electric fields

“…This concerns, for example, one-dimensional nanoribbons [21][22][23][24][25][26][27][28]. It is also notable that highly non-trivial magnetic properties of bilayer zero-dimensional nanoflakes, in particular influenced by electric field, attracted considerable attention [29][30][31][32][33][34][35]. Due to the presence of edge, magnetism can emerge in derivative graphene nanostructures even without magnetic impurities [36], while for infinite systems the adatoms or point defects are necessary for that purpose [37].…”