Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 26: Graphene - Electronic Properties and Transport 2 (jointly with DS, HL, MA, and O)
TT 26.2: Vortrag
Dienstag, 12. März 2013, 09:45–10:00, H17
Magnetoresistance of Nanocrystalline Graphene — Daniel Steininger1, •Paul Linsmaier1, Ina Schneider1, Christoph Strunk1, Matthias Büenfeld2, Nils-Eike Weber2, Andrey Turchanin2, Miriam Grothe3, and Thomas Weimann3 — 1Institute for Experimental and Applied Physics, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany — 2Faculty of Physics, University of Bielefeld,Universitätsstr.25, D-33615 Bielefeld, Germany — 3Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
We report on the magnetotransport in Hall bar structures of nanocrystalline graphene. The graphene sheets were prepared by electron-beam-induced cross-linking and subsequent pyrolysis of aromatic self-assembled monolayers [1]. The I-V characteristics show considerably non-linear behaviour at low temperatures. One low resistive sample (≈ 200 kOhm/sq at T = 4 K) shows positive magnetoresistance values up to + 20 % in the perpendicular magnetic field for temperatures below 6 K, while above this temperature the magnetoresistance becomes negative. Measurements of the transversal voltage in the linear regime exhibit anomalous behaviour which cannot be explained by the conventional Hall effect. If the magnetic field is aligned parallel to the graphene sheet the magnetorestance exhibits large positive values up to + 300 %. Measurements on a highly resistive sample (≈ 30 MOhm/sq at T = 4 K) reveal a non-monotonic behaviour of the magnetoresistance in a perpendicular magnetic field.
[1] A. Turchanin et al., ACS Nano 5 (2011) 3896-3904.