ABSTRACT
In this chapter, the authors take stock of the current achievements in this exciting field, point out certain important areas of investigation requiring more attention to fill the gaps in the level of understanding of thallium (Tl)-based high-Tc oxides, and make an attempt to envisage the future directions in the research and development of these materials. Only thereafter can some important questions such as the nature of the phase transition from the doublelayer to the corresponding single-layer thallium cuprates, the decomposition route of Tl-2223, and so on be answered. An appropriate knowledge of the phase stability of the major superconducting Tl phases would also help in the preparation of well-characterized single-phase ceramic samples, as well as growth of single crystals of high quality, both of which are the essential inputs for the evaluation of superconducting behavior of Tl-based superconductors toward a better understanding of the underlying physics, and for feasible efforts in device technology.
