Abstract
REBa(2)Cu(3)O(7-) (δ) (RE123, RE: rare earth) is one of the high-temperature superconductors with a transition temperature (T (c)) exceeding 90 K. Because of its high-T (c) and large critical current density (J (c)) 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 J (c) 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) J (c) ( Jclocal ) by a remanent magnetization method. We found that Jclocal shows a trend to be improved when four or five RE elements are mixed at the RE site, which results in high configurational entropy of mixing (ΔS (mix)). All samples exhibited an order of few MA cm(-2) which is a criterion for practical application and the highest Jclocal resulted in a value of around 7.0 MA cm(-2) at T = 2.0 K. Because high-entropy alloying can improve Jclocal of RE123 superconductors, our entropy-engineering strategy introduced here would be useful for the development of RE123 superconducting materials available under high magnetic fields.