Abstract We report the effects of thermal treatment and La doping on the Sr site in the newly discovered intergrowth superconductor TlSr4Cu2Oz(SO4), whose zero-resistivity temperature is found to be above 70 K. This new phase crystallizes in the tetragonal system (p4/mmm, a = 3.83 A, c =16.6 A). Resistivity and room-temperature thermoelectric measurements for the TlSr4Cu2Oz(SO4) samples heat-treated at temperatures below 500 °C in Ar atmosphere suggest that the as-prepared sample is under a nearly optimal hole-doped state. In the Tl(Sr4-xLax)Cu2Oz(SO4) (x = 0–1.0) system, superconductivity is suppressed as the La doping content increases, and the decrease in transition temperature with the increase in La doping content above 0.1 is accompanied by increased formation of the TlSr2CuOz phase and decomposition of the TlSr4Cu2Oz(SO4) phase, suggesting that the formation of the TlSr4Cu2Oz(SO4) phase is strongly affected by La doping on the Sr site compared with that of the TlSr2CuOz phase.

中文翻译：

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一种新型硫酸氧超导体的超导特性

摘要 我们报告了热处理和 La 掺杂对新发现的共生超导体 TlSr4Cu2Oz(SO4) 中 Sr 位点的影响，发现其零电阻温度高于 70 K。这种新相在四方晶系 (p4/嗯，a = 3.83 A，c = 16.6 A）。TlSr4Cu2Oz(SO4) 样品在低于 500 °C 的温度下在 Ar 气氛中热处理的电阻率和室温热电测量表明，所制备的样品处于近乎最佳的空穴掺杂状态。在 Tl(Sr4-xLax)Cu2Oz(SO4) (x = 0–1.0) 体系中，随着 La 掺杂量的增加，超导性受到抑制，随着 La 掺杂量的增加超过 0.1，转变温度的降低伴随着增加TlSr2CuOz 相的形成和 TlSr4Cu2Oz(SO4) 相的分解，