Giant magnetoresistance in ultrasmall graphene based devices.
By computing spin-polarized electronic transport across a finite zigzag graphene ribbon bridging two metallic graphene electrodes, we demonstrate, as a proof of principle, that devices featuring 100% magnetoresistance can be built entirely out of carbon. In the ground state a short zigzag ribbon is an antiferromagnetic insulator which, when connecting two metallic electrodes, acts as a tunnel barrier that suppresses the conductance. The application of a magnetic field makes the ribbon ferromagnetic and conductive, increasing dramatically the current between electrodes. We predict large magnetoresistance in this system at liquid nitrogen temperature and 10 T or at liquid helium temperature and 300 G.
Muñoz-Rojas
F
F
Departamento de Física Aplicada, Universidad de Alicante, San Vicente del Raspeig, E-03690 Alicante, Spain.
Fernández-Rossier
J
J
Palacios
J J
JJ