SYNTHESIS OF THALLIUM SUPERCONDUCTING PHASES VIA MELT QUENCHING

This paper focuses on the synthesis of Tl-2201, Tl-2212 and Tl-2223 phases by the melt-quench process as a means of minimizing the thallium loss. The compositions were melted at high temperatures for a short period of time and quenched between steel plates followed by a subsequent heat treatment which resulted in the formation of the Tl-2201 and Tl-2212 phases from their respective stoichiometric compositions. A low purity Tl-2223 sample was obtained by this process from its stoichiometric composition. Results from X-ray diffraction and microstructural characterization are presented. This paper also presents the results of our unsuccessful attempts to stabilize the superconducting phases in borate glass.