Impact of Zn substitution on phase formation and superconductivity of Bi1.6Pb0.4 Sr2Ca2Cu3-xZnxO10 with x = 0.0, 0.015, 0.03, 0.06, 0.09 and 0.12

TL;DR

This study investigates how substituting Zn into Bi-2223 superconductors affects their phase composition and critical temperature, revealing a slight decrease in phase purity and Tc saturation at higher doping levels, with comparisons to other HTSC systems.

Contribution

It provides new insights into the effects of Zn doping on phase stability and superconducting properties of Bi-2223, including non-monotonic Tc behavior and phase composition changes.

Findings

Superconducting Tc decreases with Zn content but saturates around 96 K for x > 0.06.

Bi-2223 phase proportion slightly decreases with increasing Zn doping.

Lattice parameters remain largely unchanged despite Zn substitution.

Abstract

Samples of series Bi1.6Pb0.4Sr2Ca2Cu3-xZnxO10 with x = 0.0, 0.015, 0.03, 0.06, 0.09 and 0.12 are synthesized by solid-state reaction route. All the samples crystallize in tetragonal structure with majority (> 90%) of Bi-2223 (Bi2Sr2Ca2Cu3O10) phase (c-lattice parameter ~ 36 A0). The proportion of Bi-2223 phase decreases slightly with an increase in x. The lattice parameters a and c of main phase (Bi-2223) do not change significantly with increasing x. Superconducting critical transition temperature (Tc) decreases with x as evidenced by both resistivity [(T)] and AC magnetic susceptibility [(T)] measurements. Interestingly the decrement of Tc is not monotonic and the same saturates at around 96 K for x > 0.06. In fact Tc decreases fast (~10K/at%) for x = 0.015 and 0.03 samples and later nearly saturates for higher x values. Present results of Zn doping in Bi-2223 system are compared with Zn doped other HTSC (High temperature superconducting) systems, namely the RE-123 (REBa2Cu3O7) and La-214 ((La,Sr)2CuO4).