Anomalous broadening of specific heat jump at Tc in high-entropy-alloy-type superconductor TrZr2

TL;DR

This study investigates how structural disorder in high-entropy-alloy-type superconductors affects their specific heat behavior near Tc, revealing a novel broadening phenomenon linked to microscopic inhomogeneity.

Contribution

It reports the first observation of broadening in the specific heat jump at Tc in TrZr2 HEA-type superconductors, highlighting disorder's impact on superconducting properties.

Findings

Specific heat jump broadens with increased mixing entropy.

Magnetization measurements remain sharp despite broadening.

Broadening correlates with microscopic inhomogeneity of Cooper pairs.

Abstract

A high-entropy-alloy-type (HEA-type) superconductor is new category of highly disordered superconductors. Therefore, finding brand-new superconducting characteristics in the HEA-type superconductors would open new avenue to investigate the relationship between structural disorder and superconductivity. Here, we report on the remarkable broadening of specific heat jump near a superconducting transition tempreature (Tc) in transition-metal zirconides (TrZr2) with different mixing entropy ({\Delta}Smix) at the Tr site. With increasing {\Delta}Smix, the superconducting transition seen in specific heat became broader, whereas those seen in magnetization were commonly sharp. Therefore the broadening of specific heat jump would be related to the microscopic inhomogeneity of the formation of Cooper pairs behind the emergence of bulk superconductivity states.