Influences of Ag doping on the high energy ball milling aided sintering FeSe superconductors

摘要

AbstractFe1.10Se and Fe1.15Se superconducting bulks were fabricated with high energy ball miling aided sintering process with different Ag nanoparticles addition. The influences of both Fe content and Ag addition on the phase composition, microstructures, critical temperature as well as the grain connectivity of these two systems have been systematically analyzed. It is noticed that with the increasing contents of both Fe and Ag addition, the content of non-superconducting hexagonal δ-FeSe phase decreased. The increasing superconducting phase volume ratio and critical temperatures were both confirmed by the magnetization measurements, which can be attributed to the Ag addition. On the other hand, the microstructures observation revealed the systematical change of texture structures and secondary phase contents, which was beneficial to the enhancement of intergrain connectivity. Therefore, the peak temperature on the imaginary component of AC susceptibility shifted towards higher temperatures with Ag addition, especially after a low oxygen atmosphere annealing process. The optimal superconducting properties were both obtained with 10 wt% Ag addition in Fe1.10Se and Fe1.15Se systems.