Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 17: Poster Session: Correlated Electrons 1

TT 17.5: Poster

Montag, 1. April 2019, 15:00–18:30, Poster D

Towards crystal growth process of isotope pure ¹⁷⁴YbRh₂Si₂ — Susanna Rongstock, •Sebastian Witt, Doan-My Tran, and Cornelius Krellner — Physikalisches Institut, Goethe University Frankfurt, D-60438 Frankfurt

A central question in condensed matter research concerns the interplay between quantum criticality and unconventional superconductivity in strongly correlated electron systems such as heavy-electron systems. Recently, superconductivity was also discovered in the quantum-critical material YbRh₂Si₂ at 2 mK [1]. So far the interplay between electronic and nuclear moments of Yb and ist impact on the superconductivity is not settled. For that reason, it is essential to investigate YbRh₂Si₂ samples with a well-defined Yb nuclear spin, with the simplest case of ¹⁷⁴Yb which has zero nuclear spin.
In this contribution, we report on the challenges to grow a ¹⁷⁴YbRh₂Si₂ crystal, as the Yb-isotopes are only available as oxides and are rather expensive. We have developed a process to reduce the oxide to metallic Yb with minimal mass losses and scaled down to established crystal growth process to work with smaller total masses. The characterization of the single crystals by different methods (Laue, PXRD, resistivity, magnetization, heat capacity) partly down to low temperatures will be presented. Besides the desired compound we present the properties of a parasitic phase, (e.g. YbRh₆Si₄).
E. Schuberth et al., Science, 351, 485-488 (2016).