Suppression of the sausaging effect in (Ba,Na)Fe2As2 round wires by using Ag1−zSnz/Cu double sheath

We report the fabrication of (Ba,Na)Fe₂As₂ round wires that are processed using the hot isostatic pressing (HIP) technique. We employed double sheaths composed of Cu and Ag_1−zSn_z alloy because they offer superior mechanical strength compared to pure Ag. The cross-sectional area of the wire core was measured using X-ray computed tomography. The findings of this study demonstrate that utilizing Ag_1−zSn_z alloy as the inner sheath material helps reduce the degree of the sausaging effect in the wire, resulting in a more uniform cross-sectional area of the wire core. However, transport critical current density (J_c) of the wires with the Ag_1−zSn_z alloy decreased gradually as the Sn content, z, increased, which may be attributed to the nonoptimized sintering temperatures during the HIP process. These results suggest that when heat-treated at an appropriate temperature during the HIP process, the use of Ag_1−zSn_z alloy holds great potential for use in high-performance applications.