Superconductivity with high upper critical field in an equiatomic high entropy alloy Sc-V-Ti-Hf-Nb

TL;DR

This study reports a new equiatomic high-entropy alloy superconductor with a high upper critical field exceeding the Pauli limit, showing potential for advanced superconducting applications.

Contribution

It introduces a novel equiatomic HEA superconductor with detailed synthesis, characterization, and demonstration of its high upper critical field surpassing the Pauli limit.

Findings

Superconductor with Tc of 4.17 K

Upper critical field exceeds Pauli limit

Crystallizes in body-centered cubic structure

Abstract

High-entropy alloy (HEA) superconductors have attracted significant attention due to their exceptional low-temperature mechanical and superconducting properties. We report the synthesis and thorough characterization of an equiatomic HEA superconductor with the composition Sc$_{0.20}$V$_{0.20}$Ti$_{0.20}$Hf$_{0.20}$Nb$_{0.20}$, crystallizing in a body-centered cubic crystal structure (Im3$\bar{m}$). Our investigation, using magnetization, transport, and heat capacity measurements, reveals the presence of weakly coupled, fully gapped superconductivity with a transition temperature of 4.17(3) K and the upper critical field exceeding the Pauli paramagnetic limit. The metallic nature, combined with a high upper critical field, positions it as a promising candidate for applications in superconducting devices.