Laser-Assisted Floating Zone Growth of BaFe2S3 Large-Sized Ferromagnetic-Impurity-Free Single Crystals

Maria Lourdes Amigó,Jochen Geck,Silvia Seiro,Andrey Maljuk,Anja U.B Wolter,Quirin Stahl,Bernd Büchner,Christian Hess,Kaustuv Manna,Claudia Felser

doi:10.3390/cryst11070758

Abstract

The quasi-one-dimensional antiferromagnetic insulator BaFe2S3 becomes superconducting under a hydrostatic pressure of ∼10 GPa. Single crystals of this compound are usually obtained by melting and further slow cooling of BaS or Ba, Fe, and S, and are small and needle-shaped (few mm long and 50–200 μm wide). A notable sample dependence on the antiferromagnetic transition temperature, transport behavior, and presence of superconductivity has been reported. In this work, we introduce a novel approach for the growth of high-quality single crystals of BaFe2S3 based on a laser-assisted floating zone method that yields large samples free of ferromagnetic impurities. We present the characterization of these crystals and the comparison with samples obtained using the procedure reported in the literature.

Highlights

Fe b c a Previously, we have reported the growth of BaFe2 S3 crystals using a Bridgman-like method based on optical heating [15]
Since BaFe2 S3 melts at a relatively low temperature of about 800 ◦ C in Ar atmosphere, the growth was performed at low laser output power (6.7–7.0%)
We show that the quality of BaFe2 S3 crystals can be greatly improved when grown by a laser-assisted floating zone method compared to that of crystals grown using the method widely reported in the literature [6,15,16]

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Since the discovery of superconductivity in LaO1−x Fx FeAs in 2008 [1], a great effort was devoted to the study of iron-based superconductors [2,3,4]. While most of the materials in this class share a layered crystalline structure [5], the finding of superconductivity in the quasi-one-dimensional iron chalcogenides BaFe2 S3 [6,7] and BaFe2 Se3 [8] represented an interesting surprise. The building blocks of these compounds are two-leg ladders of edge-sharing Fe(S,Se) tetrahedra, as shown in Figure 1 for BaFe2 S3 , that contrast with the planes of FeAs4 or FeSe4 tetrahedra common to other members of the family

Methods

Results

Conclusion