Si-induced superconductivity and structural transformations in DyRh4B4

TL;DR

This study demonstrates that silicon addition induces superconductivity and structural changes in DyRh4B4, suppressing ferromagnetism and revealing coexistence of superconductivity and antiferromagnetism in specific phases.

Contribution

It is the first to show silicon-induced superconductivity and structural transformation in DyRh4B4, linking phase composition to magnetic and superconducting properties.

Findings

Superconductivity appears below 4.5 K in Si-doped DyRh4B4.

The ferromagnetic transition at 12 K is suppressed by silicon addition.

Superconductivity and antiferromagnetism coexist in the bct-DyRh4B4 phase.

Abstract

DyRh4B4 has been known to crystallize in the primitive tetragonal (pt)-structure and to exhibit a ferromagnetic transition at 12 K, the highest magnetic transition temperature in the entire series of the RRh4B4 materials [1]. We show here that our silicon-added samples of the nominal composition DyRh4B4Si0.2 exhibit superconductivity below Tc ~ 4.5 K and an antiferromagnetic transition below TN ~ 2.7 K. The 12 K transition observed in the pt-DyRh4B4 is completely suppressed. Our annealed samples mainly consist of domains of the chemical composition DyRh3.9B4.2Si0.08. These domains contain two crystallographic phases belonging to the body-centred tetragonal (bct)-structure and the orthorhombic (o)-structure. We have reasons to suggest that superconductivity and antiferromagnetic ordering arise from bct- DyRh4B4 phase and, therefore, coexist below TN ~ 2.7 K.