The effect of the sintering process on Ag-added FeSe(0.94)superconducting wire

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 degrees C for 100 h and at 700 degrees C for 1 h, in Ag-added FeSe(0.94)superconducting wire produced using theex-situpowder-in-tube method. The crystal structure of both wires is mainly composed of the tetragonal beta-FeSe phase. Ag does not react with selenium, and it can be incorporated into the crystal structure. The transportJ(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.