High-entropy silicide superconductors with W$_{5}$Si$_{3}$-type structure

TL;DR

This paper reports the synthesis and characterization of two new high-entropy silicide superconductors with a W$_{5}$Si$_{3}$-type structure, demonstrating their superconducting properties and higher critical temperatures compared to binary counterparts.

Contribution

The study introduces the first superconducting high-entropy nonoxide ceramics with a W$_{5}$Si$_{3}$-type structure, expanding the class of high-entropy superconductors.

Findings

Both HESs are weakly coupled bulk superconductors.

They exhibit higher $T_c$ (3.2-3.3 K) than binary analogs.

They have the largest $B_{c2}(0)/T_c$ ratios among similar structural superconductors.

Abstract

We report the synthesis, crystal structure and physical properties of two new high-entropy silicides (HESs), namely (Nb$_{0.1}$Mo$_{0.3}$W$_{0.3}$Re$_{0.2}$Ru$_{0.1}$)$_{5}$Si$_{3}$ and (Nb$_{0.2}$Mo$_{0.3}$W$_{0.3}$Re$_{0.1}$Ru$_{0.1}$)$_{5}$Si$_{3}$. Structural analysis indicates that both HESs consist of a (nearly) single tetragonal W$_{5}$Si$_{3}$-type phase (space group $I$4/$mcm$) with a disordered cation distribution. Electrical resistivity, magnetic susceptibility and specific heat measurements show that (Nb$_{0.1}$Mo$_{0.3}$W$_{0.3}$Re$_{0.2}$Ru$_{0.1}$)$_{5}$Si$_{3}$ and (Nb$_{0.2}$Mo$_{0.3}$W$_{0.3}$Re$_{0.1}$Ru$_{0.1}$)$_{5}$Si$_{3}$ are weakly coupled bulk superconductors, which represent the first superconducting high-entropy nonoxide ceramics. In particular, these HESs have higher $T_{\rm c}$ values (3.2-3.3 K) compared with those of the binary counterparts, and their $B_{\rm c2}$(0)/$T_{\rm c}$ ratios are the largest among superconductors of the same structural type.