Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 18: Superconductivity: Borides, Borocarbides, Carbides, ...
TT 18.9: Vortrag
Dienstag, 28. März 2006, 17:15–17:30, HSZ 02
Single crystal X-ray diffraction analysis and electron density calculation of YNi2B2C — •T. Leisegang1, D. C. Meyer1, P. Paufler1, D. Souptel2, G. Behr2, O. Ignatchik3, A. Ormeci4, H. Rosner4, and J. Wosnitza5 — 1ISP, TU Dresden, Germany — 2IFW-Dresden, Germany — 3IFP, TU Dresden, Germany — 4MPI-CPfS, Germany — 5HLD Dresden, FZ Rossendorf, Germany
The quaternary borocarbide YNi2B2C, space group (139) I4/mmm, exhibits superconductivity (Tc ≈ 15 K) as was first reported in [1]. This superconducting behaviour depends strongly on the crystal composition within the small homogeneity range and on the crystal growth conditions. Here we report on investigations of two different samples, namely bulk samples grown by a floating zone technique [2] and plate samples grown by a flux-growth method [3]. De Haas-van Alphen (dHvA) measurements were performed to determine the electronic band structure as well as the evolution of a superconducting energy gap at the Fermi surface [4]. To evaluate the exact crystal structure, single-crystal X-ray diffraction measurements at room temperature were performed. Different models of structural disorder were refined and a difference-Fourier analysis was carried out. The experimental electron density will be compared with theoretical calculations. The work was supported by the Deutsche Forschungsgemeinschaft (SFB 463).
[1] Nagarajan et al., Phys. Rev. Lett. 72, 274 (1994).
[2] Souptel et al., J. Cryst. Growth 276, 652 (2005).
[3] Canfield et al., Phys. Today 51, 40 (1998).
[4] Ignatchik et al., J. Magn. Magn. Mat. 290-291, 424 (2005).