Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 24: Carbon-based Nanostructures
HL 24.5: Vortrag
Dienstag, 8. März 2016, 11:00–11:15, H14
Magnetotransport properties of a disordered graphite microwire produced by He+ bombardment and embedded in a diamond crystal — •Jose Barzola-Quiquia1, Tobias Lühmann2, Ralf Wunderlich1, Mahsa Zoraghi1, Jan Meijer1, and Pablo Esquinazi1 — 1Institute for Experimental Physics II, University of Leipzig, 04103 Leipzig, Germany — 2Institute for Medicine Physics and Biophysics, University of Leipzig, 04107 Leipzig, Germany
We have investigated the magnetotransport properties of a graphite-like microwire (GLM) embedded in a diamond crystal in the temperature range of 2 K to 300 K and magnetic field to ± 8 T. The GLM was produced at ≈ 3 µm below the surface of a diamond crystal through the implantation of He+ ions of 1.8 MeV energy using a microbeam. The initial wire was amorphous and was crystallised after heat treatment at T≈ 1475 K. After a first annealing treatment the electrical transport at low temperatures is well described by a fluctuation-induced tunneling conductance model. The tunneling process occurs between the partially graphitized grains separated by nearly insulating thin amorphous regions. After a second annealing the transport mechanism changes to variable range hopping conduction. A finite magnetoresistance (MR) was observed at temperatures T<250 K, which can be well described by a semi-empirical model that takes into account a spin dependent scattering process. The magnetic properties indicate the existence of magnetic order in the GLM. The appearance of the graphitic structure after annealing treatment was confirmed by confocal Raman spectroscopy.