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Electronic Properties of Nanopore Edges of Ferromagnetic Graphene Nanomeshes at High Carrier Densities under Ionic-Liquid Gating

DOI: 10.4236/msa.2014.51001    3,261 Downloads   5,411 Views   Citations


Graphene edges with a zigzag-type atomic structure can theoretically produce spontaneous spin polarization despite being a critical-metal-free material. We have demonstrated this in graphene nanomeshes (GNMs) with honeycomb-like arrays of low-defect hexagonal nanopores by observing room-temperature ferromagnetism and spin-based phenomena arising from the zigzag-pore edges. Here, we apply extremely high electric fields to the ferromagnetic (FM) GNMs using an ionic-liquid gate. A large on/off-ratio for hole current is observed for even small applied ionic-liquid gate voltages (Vig). Observations of the magnetoresistance behavior reveal high carrier densities of ~1013 cm-2 at large Vig values. We find a maximum conductance peak in the high -Vig region and its separation into two peaks upon applying a side-gate (in-plane external) voltage (Vex). It is discussed that localized edge-π band with excess-density electrons induced by Vig and its spin splitting for majority and minority of spins by Vex (half-metallicity model) lead to these phenomena. The results must realize critical-element-free novel spintronic devices.

Conflicts of Interest

The authors declare no conflicts of interest.

Cite this paper

T. Hashimoto, S. Kamikawa, Y. Yagi and J. Haruyama, "Electronic Properties of Nanopore Edges of Ferromagnetic Graphene Nanomeshes at High Carrier Densities under Ionic-Liquid Gating," Materials Sciences and Applications, Vol. 5 No. 1, 2014, pp. 1-9. doi: 10.4236/msa.2014.51001.


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