Stabilization of new superconducting thallium cuprates and oxycarbonates by molybdenum

Oxyanions in perovskites: from superconductors to solid oxide fuel cells

“…34,35 The above carbonate containing materials may be classed as intergrowth phases of layered CaCuO 2 and Ba 2 CuO 2 CO 3 , and many such intergrowth structures consisting of an existing superconductor and (Sr/Ba) 2 -CuO 2 CO 3 layers have been developed. [36][37][38][39][40][41][42][43][44] The intergrowth structure is based on the assumption that CuO 2 is common to both the (Sr/Ba) 2 CuO 2 CO 3 and the existing superconductor component. There are many superconductors with this type of structure, another example being Tl 0.5 A 0.5 Sr 4 Cu 2 CO 3 O 7 (A = Pb, Bi).…”

“…A sulphate containing analogue of the above has also been prepared, with a T c of 50 K. 45 In addition to Pb and Bi substitution, transition metals, such as Mo, Cr and V, can be substituted. 41,42,[46][47][48][49] Intergrowth structures have also been prepared based on other superconductors, e.g. (Bi 2 Sr 2 CuO 6 ) n (Sr 2 CuO 2 CO 3 ) m , 50,51 and (NdSr 2 Cu 2 BO 7 )-(NdSrCuO 2 BO 3 ), 52 the latter an interesting example where borate is present in both components of the intergrowth structure.…”

Investigation into the Effect of Sulfate and Borate Incorporation on the Structure and Properties of SrFeO3-δ

“…Research on oxyanion incorporation into perovskites was initially reported for superconducting cuprate materials. This work showed that a wide range of oxyanions (carbonate, borate, nitrate, sulfate, and phosphate) could be incorporated into the perovskite structure [5][6][7][8][9][10][11][12]. In this doping strategy, the central ion of the oxyanion group is located on the perovskite B cation site, with the oxygens of this group occupying either three (borate, carbonate, nitrate) or four (sulfate, phosphate) of the available six anion positions around this site, albeit suitably displaced to achieve the correct coordination for the oxyanion group.…”

The Superconducting Copper Oxychromate Tl3(CrO4)Sr8Cu4O16: Long-Range Ordering between Thallium and Chromium

“…Among the numerous layered thallium cuprates, the “1201” oxides exhibit distinct behavior since very few of them are superconductors. The cuprates TlSr 2 CuO 5 - δ − and Tl 1 - x Mo x Sr 2 CuO 5 - δ have never shown any signature of superconductivity. In contrast, superconductivity below 40 K has been observed in the cuprates Tl 0.5 Bi 0.5 Sr 2 CuO 5 - δ , and Tl 1 - x Pr x Sr 2 - y Pr y CuO 5 - δ , but for these compounds, the diamagnetic volume fraction was found to be small (less than 5%).…”