Historical Perspective on the Discovery of Tl-Based HTSC Oxides

The search for high-temperature superconductivity has proceeded from two rather separate sources of motivation. Empirical work on binary and ternary compound superconductors and oxides (for a comprehensive review, see Ref. 1) brought the critical temperature of superconductors to 23 K in the early 1970s, a critical temperature not to be exceeded until the discovery of superconductivity in the Cu-O system in 1986 by Bednorz and Müller [2].