Hot pressing to enhance the transport J(c) of Sr(0.6)K(0.4)Fe(2)As(2) superconducting tapes

High-performance Sr(0.6)K(0.4)Fe(2)As(2) (Sr-122) tapes have been successfully fabricated using hot pressing (HP) process. The effect of HP temperatures (850–925°C) on the c-axis texture, resistivity, Vickers micro-hardness, microstructure and critical current properties has been systematically studied. Taking advantage of high degree of c-axis texture, well grain connectivity and large concentration of strong-pinning defects, we are able to obtain an excellent J(c) of 1.2 × 10(5) A/cm(2) at 4.2 K and 10 T for Sr-122 tapes. More importantly, the field dependence of J(c) turns out to be very weak, such that in 14 T the J(c) still remains ~ 1.0 × 10(5) A/cm(2). These J(c) values are the highest ever reported so far for iron-pnictide wires and tapes, achieving the level desired for practical applications. Our results clearly strengthen the position of iron-pnictide conductors as a competitor to the conventional and MgB(2) superconductors for high field applications.