Effect of Li2O on the microstructure, magnetic and transport properties of Tl-2223 superconductor

• We synthesize and investigate the addition of Li2​O in Tl2Ba2Ca2Cu3O10 (Tl-2223) superconductor.
• We present evidences (e.g. lattice parameters, Tc, and Jc changes) that Li goes into Tl-2223 structure.
• It is interesting that during synthesis the initial thallium content can be easily reduced by 40% without great change in Tc while Li improves the superconducting volume fraction.
• Short-time thermal annealing under flowing Ar + 4%H2 (1 h) further improves the superconducting volume fractions, as well as Jc.

The present study gives an account of the effect of addition of Li2O on the ease of phase formation and superconducting properties of Tl2Ba2Ca2Cu3O10 + δ (Tl-2223) material. Li2O slightly decreases the superconducting transition temperature, while an optimal concentration of 20% Li2O improves the critical current density (Jc) by about two fold. We also found substantial effects on the synthesis temperature, microstructure and normal state transport properties of Tl-2223 with Li2O addition. Short-time annealing under flowing Ar + 4%H2 (1 h) further improves the superconducting volume fractions, as well as Jc.