Bi2-xHgxSr2-yBayCa2Cu2O10/Ag Sheath HTSC Wires, (Hg, Ba) Substitution Effect on the Critical Temperature

Abstract

Bi2-xHgxSr2-yBayCa2Cu3O10 High Temperature Superconductor (HTSC) has been prepared as a pellet by solid state reaction with a certain substitution percentages (0,0.05,0.1) of Hg and Ba substitution instead of Bi and Sr respectively. Then, HTSC wires were fabricated from the prepared superconductor pellets using powder in tube (PIT) method utilizing silver as the tube material. The prepared wires are of three types; with monofilament MOF, 9 multifilament core 9MF and 81 filaments core(81MF). Several cycles of mechanical drawing and rolling process performed to the starting silver tube of 0.4cm diameter and 5cm length to minimize the filament diameter. The average filament diameter with 81MFC wire was about 25μm measured with an optical microscope.Tc critical temperature for superconductivity is measured for the pellets and wires using four point probes techniques. These results show that the substation Bi by Hg give a rise to the superconductor to improve highly Tc, while substitution Sr with Ba lowers Tc.substitution of 0.05, 0.1 Hg to the composition Bi2-xHgxSr2-yBayCa2Cu3O10 will raise the transition temperature (Tc). Also substitution of Sr by Ba decreases the transition temperature (Tc), Hg(0.05 – 0.1) substitution still raise Tc after substitution of Ba with (0.05 – 0.1). High – Tc phase (2223), 2221 phase in B-2223 system and the addition of Ag to silver sheaths and a small amount of impurity phases appear in the result of XRD analysis.