Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 1: Superconductivity - Fabrication, Technical Optimization and Characterization

TT 1.1: Vortrag

Freitag, 4. März 2005, 10:15–10:30, TU H104

Boron-doped Diamond Films — •H.C. Freyhardt¹, K. Winzer², D. Bogdanov², P.J. Wilbrandt¹, M. Malchow¹, L. Schäfer³, and J. Wurm⁴ — ¹Institut für Materialphysik und — ²1. Physikalisches Institut der Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen — ³Fraunhofer-Institut Schicht u. Oberflächentechnik, Bienroder Weg 54E, 38108 Braunschweig — ⁴METAKEM GmbH, Achtzehnmorgenweg 3, 61250 Usingen

After superconductivity was reported in bulk high-pressure synthesized B containing diamond, B-doped diamond films were deposited on polycrystalline W and single-crystalline Si substrates by a hot-filament activated chemical vapour deposition process. The polycrystalline films exhibit lattice constants which are slightly larger than for pure diamond. Whereas films on W are under compressive stresses, films on Si are almost stress-free. The nominal B-concentration varied between 2700 and 5200 ppmB and was checked by SIMS and Raman spectroscopy. Superconductivity was observed in all samples with a transition temperature T_c up to 3.3K for 5200 ppmB. The T_c increases with the B content and the transition width was found to be 0.2K for the best sample. Upper critical fields B_C2(0) are scaling with T_c and reach 3.6T. It will be discussed whether superconductivity can be described by a BCS-like behaviour.