Effects of heat treatment temperature on the superconducting properties of Ba1−x K x Fe2As2 tapes

In this study, the effects of heat treatment temperature on superconducting properties were systematically studied by sintering silver-sheathed Ba1−x K x Fe2As2 tapes at different temperatures. The transport J c increases as the sintering temperature rises from 700 °C to 850 °C. The optimized J c values of tapes sintered at 900 °C and 850 °C reach 6.2 × 104 A cm−2 (4.2 K and 10 T) which represent a very high J c level for flat rolled mono-core silver-sheathed iron-based superconducting wires and tapes. The properties of tapes sintered at different temperatures were investigated, including grain crystallinity, core density, c-axis texture and elemental distribution. The results demonstrate that 850 °C is a suitable temperature to fabricate silver-sheathed Ba1−x K x Fe2As2 superconducting tapes.