We investigated the effect of different sintering processes on Ag–added FeSe 0.94 superconducting wires. After applying different sintering procedures, we successfully obtained zero resistivity, at 350 °C for 100 h and at 700 °C for 1 h, in Ag–added FeSe 0.94 superconducting wire produced using the ex-situ powder-in-tube method. The crystal structure of both wires is mainly composed of the tetragonal β –FeSe phase. Ag does not react with selenium, and it can be incorporated into the crystal structure. The transport J c value of these wires is calculated to be 24.4, and 38 A cm −2 at 4.2 K in a self-field, respectively. The low current densities of the wires are attributed to the low core–density and the presence of porosity. The upper critical field is estimated to be 16.2 and 14.6 T from Werthamer–Helfand–Hohenberg theory, respectively.

中文翻译：

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烧结工艺对添加Ag的FeSe 0.94超导线材的影响

我们研究了不同烧结工艺对添加Ag的FeSe 0.94超导线材的影响。在采用不同的烧结程序后，我们成功地在350°C的条件下100 h和在700°C的条件下1 h取得了零电阻率，该电阻率是使用异位管内粉末法生产的添加有Ag的FeSe 0.94超导线中的。两条线的晶体结构主要由四方β-FeSe相组成。Ag不与硒反应，可以掺入晶体结构中。这些线的传输J c值在自场中在4.2 K时分别计算为24.4和38 A cm -2。电线的低电流密度归因于低的芯线密度和孔隙率的存在。根据Werthamer–Helfand–Hohenberg理论，最高临界场估计分别为16.2和14.6T。