Methods to produce Tl(1223) tapes with improved properties

Different methods to prepare superconducting mono-and multifilamentary Tl(1223) tapes were developed. High-purity ceramics could be produced by ex-situ or in-situ reaction under a high isostatic gas pressure. Tapes prepared by the PIT method and an in-situ reaction carried out close to the melting point of the oxide were relatively dense and textured. Interesting results were obtained for samples where part of the oxygen atoms in Tl(1223) had been substituted by fluorine. Critical current densities up to 20'000 A/cm(2) (77 K, 0 T) were reached for tapes produced by the PIT method. Well textured samples were obtained by electrophoretic deposition, the deposited Tl(1223) grains being produced by a synthesis involving substantial melting.