Dresden 2003 – scientific programme
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TT: Tiefe Temperaturen
TT 14: Postersitzung III (Neue u. unkonventionelle Supraleiter, Anwendungen der Supraleitung, Dünne Schichten, JJs und SQUIDs, Schwere Fermionen, Kondo-Systeme)
TT 14.4: Poster
Wednesday, March 26, 2003, 14:30–19:00, P2c
Synthesis and physical properties of MgB2 and LiBC intermetallics — •Dmitri Souptel1, Günter Behr1, Wolfgang Löser1, and Zakir Hussain2 — 1Leibniz Institute for Solid State and Materials Research Dresden, PF 27 01 16, D-01171 Dresden, Germany — 2Max-Planck-Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany
Small plate-like single crystals of the superconducting intermetallic MgB2 compound and the LiBC compound, which was predicted as a possible candidate for high-Tc superconductivity were grown by Mg-Cu-B and Li-B-C melt flux methods, respectively. Peritectically formed MgB2-particles display the highest transition temperature of Tc = 39.2 K and a narrow transition width of Δ Tc = 1.3 K. Other samples exhibit various superconducting transitions from Tc = 39 K to 7.2 K. This variation of Tc is attributed to a finite homogeneity range of the MgB2 compound. Extrinsic semi-conducting behaviour of the single-phase LiBC with an activation energy of 18 meV and a maximum specific resistivity of 2.5 Ωcm at 300 K was revealed by electrical resistivity measurements. In contrast to the theoretical prediction no superconducting features down to 2 K were detected in LiBC so far.