Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 19: Poster Session: Correlated Electrons 1

TT 19.13: Poster

Montag, 20. März 2017, 15:00–19:00, P2-EG

Advancing the crystal quality and dimensions in the crystal growth process of Yb(Rh_1−xIr_x)₂Si₂ — •Sebastian Witt¹, Michael Baenitz², and Cornelius Krellner¹ — ¹Goethe University Frankfurt, 60438 Frankfurt am Main, Germany — ²MPI for Chemical Physics of Solids, 01187 Dresden, Germany

In the heavy fermion compound, YbRh₂Si₂, a superconducting phase transition at 2mK was found recently [1]. From these measurements it is further evident, that the occurence of nuclear antiferromagnetic order slightly above T_C plays an essential role. Single crystals (SC) with isotope pure silicon and/or ytterbium enable the investigation of the nature of the superconductivity in this material. Additionaly, the stability of the superconduction phase can be investigate by the substitution of rhodium by iridium. Due to small amounts of the isotopes and the non-nominal and non-homogenous substitution it is necessary to further optimize the crystal growth.

Here, we report the crystal growth of Yb(Rh_1−xIr_x)₂Si₂ with the optimized accelerated crucible rotation technique. This technique enhances the crystal quality (homogeneity, less distortions and reduced flux inclusions). The process optimization is accompanied by resistivity measurements of the SCs as well as EDX measurements to ensure the homogeneity of the substituted elements. We report simulations of the growth process inside the crucible. Crystals with the silicon-29 isotope were used for first NMR measurements and results of metallothermic reduction of Yb₂O₃ to obtain the Yb-metal were presented.

[1] E. Schuberth et al., Science, 351(6272), 485-488, (2016).