Dresden 2006 – wissenschaftliches Programm
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MM: Metall- und Materialphysik
MM 18: Materials Design
MM 18.4: Vortrag
Dienstag, 28. März 2006, 15:30–15:45, IFW B
Synthesis and properties of new materials in the B-C system — •Natalia Dubrovinskaia1,2, Georg Eska1, Grigorii A. Sheshin 1,3, Leonid Dubrovinsky2, and Hans F. Braun1 — 1Physikalisches Institut, Universität Bayreuth, 95440 Bayreuth, Germany — 2Bayerisches Geoinstitut, Universität Bayreuth, 95440 Bayreuth, Germany — 3B. Verkin Institute for Low Temperature Physics and Engineering, 61103 Kharkov, Ukraine
Synthesis of a series of bulk samples of B-doped diamonds was realized in a wide spectrum of pressures and temperatures (up to 20 GPa and 2700 K) using a 5000 tonne multianvil press. The properties of the samples were characterized using X-ray diffraction, SEM, TEM, and microprobe analysis. Electrical resistance of the samples was measured at the temperature range between 300 K and 10 mK. It was found that the samples exhibit semiconducting an superconducting behavior at different temperature intervals. A bulk sample (~7.5 mm3) of heavily boron-doped diamond containing 2.6(0.6) at.% B was synthesized by means of direct reaction between boron carbide and graphite. Electrical resistance measurements revealed a transition to superconducting state at 2.4 K to 1.4 K. Sharpening of the temperature interval of the transition to superconducting state in magnetic field suggests that superconductivity in our samples may arise from filaments of zero-resistant material. Crystallographic aspects in explanation of the observed electrical properties will be discussed.