Single crystal growth of YbRh2Si2 and YbIr2Si2

TL;DR

This paper details the successful growth of high-quality single crystals of YbRh2Si2 and YbIr2Si2 using a high-temperature indium-flux method, and investigates their structural and electronic properties, including alloy series and crystallographic modifications.

Contribution

It introduces an optimized crystal growth technique for YbRh2Si2 and YbIr2Si2, and provides detailed structural and electronic characterization of these heavy-fermion compounds.

Findings

Large, clean single crystals were successfully grown.

Resistivity measurements show sample-dependent behavior below 10 K.

Two crystallographic modifications of YbIr2Si2 were identified.

Abstract

We report on the single crystal growth of the heavy-fermion compounds YbRh2Si2 and YbIr2Si2 using a high-temperature indium-flux technique. The optimization of the initial composition and the temperature-time profile lead to large (up to 100 mg) and clean (\rho_0=0.5 \mu\Omega cm) single crystals of YbRh2Si2. Low-temperature resistivity measurements revealed a sample dependent temperature exponent below 10 K, which for the samples with highest quality deviates from a linear-in-T behaviour. Furthermore, we grew single crystals of the alloy series Yb(Rh_(1-x)Ir_x)2Si2 with 0<x<0.23 and report the structural details. For pure YbIr2Si2, we establish the formation of two crystallographic modifications, where the magnetic 4f-electrons have different physical ground states.