Tunneling magnetoresistance phenomenon utilizing graphene magnet electrode

Journal Article · Mon Nov 03 00:00:00 EST 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4901279· OSTI ID:22391913

Hashimoto, T.; Kamikawa, S.; Soriano, D. ^[1]; Pedersen, J. G. ^[1]; Roche, S. ^[1]

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1. Institut Català de Nanociència i Nanotecnologia (ICN2), Campus de la UAB, Edifici ICN2, 08193 Bellaterra, Barcelona (Spain)

Using magnetic rare-metals for spintronic devices is facing serious problems for the environmental contamination and the limited material-resource. In contrast, by fabricating ferromagnetic graphene nanopore arrays (FGNPAs) consisting of honeycomb-like array of hexagonal nanopores with hydrogen-terminated zigzag-type atomic structure edges, we reported observation of polarized electron spins spontaneously driven from the pore edge states, resulting in rare-metal-free flat-energy-band ferromagnetism. Here, we demonstrate observation of tunneling magnetoresistance (TMR) behaviors on the junction of cobalt/SiO{sub 2}/FGNPA electrode, serving as a prototype structure for future rare-metal free TMR devices using magnetic graphene electrodes. Gradual change in TMR ratios is observed across zero-magnetic field, arising from specified alignment between pore-edge- and cobalt-spins. The TMR ratios can be controlled by applying back-gate voltage and by modulating interpore distance. Annealing the SiO{sub 2}/FGNPA junction also drastically enhances TMR ratios up to ∼100%.

• OSTI ID: 22391913
• Journal Information: Applied Physics Letters, Vol. 105, Issue 18; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COBALT
FERROMAGNETISM
GRAPHENE
HYDROGEN
MAGNETORESISTANCE
NANOSTRUCTURES
SILICA
SILICON OXIDES
SPIN
TUNNEL EFFECT