The effect of silver doping on the properties of Bi1/6Pb0/4Sr2Ca2Cu3Oδ superconductor

In this research, the effect of silver doping on 2223 phase of
ceramic superconductor Bi1.6Pb0.4Sr2Ca2Cu3Oδ (BSCCO) has been
investigated. To synthesis the samples, we used solid-state reaction method
and two different doping methods, namely, doping samples during making
processes (batches No.1) and doping samples after making superconductor
(batch No.2). With doping Ag to BSCCO, the critical temperature Tc (mid)
increases (batch No.1) and also the resistance of the normal state for all
samples decreases. For batch No.1 samples, the Jc decreases from pure
sample with increasing of Ag doping up to 2% but it increases to maximum
value by increasing Ag doping in 5 and 15 percent. The Jc in batch No.2
decreases from pure sample to 5% Ag of doped samples and then increases
by increasing Ag doping up to 20% and finally decreases to 60%. The SEM
images of samples have shown that all surfaces are porous and the grains are
platelike. The EDX analysis confirms that the primary elements in our
samples are Bi, Pb, Sr, Ca, Cu, and Ag. The XRD patterns indicated that the
silver peaks form separate phase. Also by adding Ag to BSCCO, the BSCCO
peaks slightly shifted. Therefore, the lattice parameters slightly change, but
the structure of samples has been left orthorhombic.