We report the fabrication of small (Ba,A)Fe₂As₂ (A: Na, K) coils using 10 m-class long round wires, fabricated by the powder-in-tube method. Coils are sintered using the hot-isostatic-press technique after glass-fiber insulations are installed. Critical current (I _c) of the whole coil using (Ba,Na)Fe₂As₂ and (Ba,K)Fe₂As₂ are 60 A and 66 A under the self-field, and the generated magnetic fields at the center of the coil reach 2.6 kOe and 2.5 kOe, respectively. Furthermore, the largest transport critical current density (J _c) and I _c in (Ba,Na)Fe₂As₂ wires picked up from the coil reach 54 kA cm⁻² and 51.8 A at T = 4.2 K under a magnetic field of 100 kOe, respectively. This value exceeds transport J _c of all previous iron-based superconducting round wires. Texturing of grains in the core of the wire due to the improvement of the wire drawing process plays a key role for the enhancement of J _c.

我们报告了使用 10 m 级长圆线制造小型 (Ba, A )Fe ₂ As ₂ ( A : Na, K) 线圈，通过管内粉末方法制造。在安装玻璃纤维绝缘材料后，使用热等静压技术烧结线圈。使用(Ba,Na)Fe ₂ As ₂和(Ba,K)Fe ₂ As ₂的整个线圈的临界电流（I _c）在自场下分别为60 A和66 A，中心产生的磁场线圈的电流分别达到 2.6 kOe 和 2.5 kOe。此外，最大输运临界电流密度 ( J _c ) 和I _c 在 (Ba,Na)Fe ₂ As 中，从线圈拾取的₂根导线在100 kOe 的磁场下在T = 4.2 K 时分别达到 54 kA cm ^-2和 51.8 A。该值超过运输Ĵ _Ç所有先前的铁系超导圆电线。由于拉丝工艺的改进，线芯中晶粒的织构对于提高J _c起着关键作用。