Berlin 2005 – scientific programme

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TT: Tiefe Temperaturen

TT 1: Superconductivity - Fabrication, Technical Optimization and Characterization

TT 1.2: Talk

Friday, March 4, 2005, 10:30–10:45, TU H104

Superconductivity on boron-doped diamond plates — •Dmitrij Bogdanov¹, Klaus Winzer¹, and Christoph Wild² — ¹I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen — ²Fraunhofer Institut für Angewandte Festkörperphysik, Tullastr. 72, 79018 Freiburg i. Br.

We study boron-doped diamond plates prepared by the microwave-plasma-CVD technique. In contrast to diamond films on silicon substrates the absence of a substrate allows unequivocal measurements of the electrical resistivity and of the Hall coefficient of the doped diamond. The samples show semiconducting behaviour in the non-superconducting state down to the critical temperatures between 0,4 K < T_C < 4 K. The upper critical fields B_C2(0) scale with the transition temperatures T_C; their values are up to 3 tesla. The hole concentrations were determined by the measurements of the Hall coefficient at temperatures near T_C. The correlation of the calculated density of states N(E_F) and T_C will be compared with different theoretical models.