Tunneling magnetoresistance phenomenon utilizing graphene magnet electrode

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-term...

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Bibliographic Details
Published in:Applied physics letters 2014-11, Vol.105 (18)
Main Authors: Hashimoto, T., Kamikawa, S., Soriano, D., Pedersen, J. G., Roche, S., Haruyama, J.
Format: Article
Language:English
Subjects:
Applied physics
Atomic structure
CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
COBALT
Electrodes
Electron spin
Ferromagnetic materials
FERROMAGNETISM
GRAPHENE
Honeycomb construction
HYDROGEN
MAGNETORESISTANCE
Magnetoresistivity
NANOSTRUCTURES
Porosity
SILICA
Silicon dioxide
SILICON OXIDES
SPIN
TUNNEL EFFECT
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Summary: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/SiO2/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 SiO2/FGNPA junction also drastically enhances TMR ratios up to ∼100%.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4901279