Abstract
Fluorine was found to affect the phase formation and superconducting properties of Tl-based superconductors. By varying x in (Tl0.5Pb0.5)Sr1.6Ba0.4Ca2Cu3OyFx, synthesized superconductors, an increase was found in the transition temperature and critical current density. These improvements in the superconducting properties are discussed in terms of partial substitution of fluorine into the oxygen sites which in turn affects the hole doping in this material. Structure, microstructure and elemental analysis by XRD, SEM and EDX techniques are reported; the latter of which shows the fluorine distribution.