Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 10: Superconductivity: Fabrication and Characterization
TT 10.4: Vortrag
Montag, 25. Februar 2008, 14:45–15:00, H 3010
Growth and study of LuNi2B2C single crystals — •Anke Köhler1, Günter Behr1, Beate Bergk2, Günter Fuchs1, Konstantin Nenkov1, and Joachim Wosnitza2 — 1IFW Dresden, D-1171 Dresden — 2Forschungszentrum Dresden-Rossendorf, D-01328 Dresden
Rare earth-nickel-borocarbides have attracted much interest in the last years because the compounds show the interplay of superconductivity and magnetic ordering. LuNi2B2C can be considered as non-magnetic reference system of such magnetic borocarbides as HoNi2B2C in which superconducting and antiferromagnetic ordering temperatures, Tc and TN, are similar.
So far, LuNi2B2C crystals were only prepared by a flux method. For growing larger crystals we used an optical floating zone (FZ) technique, which already was successful in crystal growth of other RNi2B2C (R = Y,Tb,Ho,Tm,Er) compounds. In the case of LuNi2B2C, the primary crystallization field is far from the stoichiometric composition, and adjacent to the properitectic LuB2C2 phase field an extended region of LuNiBC occurs. Systematic studies of polycrystalline samples revealed that samples with nominal compositions LuNi5B3.5C and LuNi5B3C0.5 are free of the properitectic LuB2C2 and LuNiBC phases. Thus in the FZ crystal growth experiments we used a molten zone which corresponds to these compositions.
From the grown LuNi2B2C rods single crystalline pieces have been prepared to investigate Fermi surface peculiarities by magneto-resistance measurements and to study the electronic band structure.