Improvement of local critical current density of REBa2Cu3O7-d by the increase in configurational entropy of mixing at the RE site

TL;DR

This study demonstrates that increasing the configurational entropy of mixing at the rare earth site in REBa2Cu3O7-d superconductors enhances local critical current density, offering a new approach to improve superconductor performance under magnetic fields.

Contribution

The paper introduces an entropy-engineering strategy using high-entropy alloying at the RE site to improve the local critical current density in REBa2Cu3O7-d superconductors.

Findings

Jclocal improves with four or five RE elements at the RE site

High configurational entropy correlates with enhanced Jclocal

Entropy engineering can be combined with other techniques for better performance

Abstract

REBa2Cu3O7-d (RE123, RE: rare earth) is one of the high-temperature superconductors with a transition temperature (Tc) exceeding 90 K. Because of its high Tc and large critical current density (Jc) under magnetic fields, RE123 superconductors have been expected to play a key role in superconductivity application. To accelerate application researches on RE123-based devices, further improvements of Jc characteristics have been desired. In this study, we investigated the effects of high-entropy alloying at the RE site on the superconducting properties, through the measurements of local (intra-grain) Jc (Jclocal) by a remanent magnetization method. We found that Jclocal shows a trend to be improved when four or five RE elements are solved at the RE site, which results in high configurational entropy of mixing (delta_Smix). Because high-entropy alloying can improve Jclocal of RE123 superconductors by modification of the RE site composition and delta_Smix, and the technique would be applicable together with other techniques, such as introduction of nanoscale disorders, our entropy-engineering strategy introduced here would be useful for development of RE123 superconducting materials available under high magnetic fields.