With excellent superconducting properties such as high T c , large H c2 , small anisotropy, and large J c , developments of superconducting wires and tapes of iron-based superconductors (IBSs) have been undertaken with promising results. So far, K-doped 122-type IBSs have been mainly developed for such purposes. Here, efforts to fabricate Na-doped 122-type IBS, (Ba,Na)Fe 2 As 2 , are presented. With the help of hot isostatic pressing (HIP) process, excellent J c characteristics of up to 44 kA cm −2 at 4.2 K under 100 kOe have been achieved. Detailed characterizations of (Ba,Na)Fe 2 As 2 HIP round wire are presented. On the other hand, discoveries of new IBSs continue, with CaKFe 4 As 4 as one of recent examples. CaKFe 4 As 4 belongs to a new family of IBSs with 1144 structure, where Ca and K occupy the Ba site in BaFe 2

中文翻译：

---

（Ba，Na）Fe 2 As 2和CaKFe 4 As 4 HIP圆线的发展

具有优良的超导性能，例如高T c，大H c2，各向异性小和大J c，铁基超导体（IBSs）的超导线和带的开发已经取得了可喜的结果。到目前为止，主要是为了这种目的而开发出掺K的122型IBS。在此，提出了制造Na掺杂的122型IBS（（Ba，Na）Fe 2 As 2）的努力。借助于热等静压（HIP）工艺，在100 kOe下于4.2 K下获得了高达44 kA cm -2的出色J c特性。介绍了（Ba，Na）Fe 2 As 2 HIP圆线的详细特性。另一方面，新的IBS的发现仍在继续，CaKFe 4 As 4是最近的例子之一。CaKFe 4 As 4属于具有1144结构的IBS新家族，其中Ca和K占据BaFe 2中的Ba位点