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Dependence of Tc and the Crystal Structure of Tl2-zBa2Ca1.95Y0.05Cu3Oy Superconducting Oxide on the Tl Content.

2002; Ceramic Society of Japan; Volume: 110; Issue: 1279 Linguagem: Inglês

10.2109/jcersj.110.180

1882-1022

Yasushi Idemoto, Jun Nishikawa, Nobuyuki KOURA, Takashi Kamiyama, Fujio Izumi,

Physics of Superconductivity and Magnetism

Superconductors, Tl2-zBa2Ca1.95Y0.05Cu3Oy, with variable Tl contents were prepared. We investigated the dependence of their properties, crystal structures and Tc on the Tl content. The Cu valence decreased with decreasing Tl content, 2-z, in the region of 2-z≥1.5 but increased in the region of 1.2≤2-z<1.5. The critical temperature, Tc changed with decreasing Tl content. Tc(zero) was 116 K at 2-z=1.7. When the Tl content was decreased, Tc(zero) reached the maximum value of 119 K at 2-z=1.2. The results of structure refinements of samples with different Tl contents with neutron powder diffraction data show that Cul-Ca, Y and Cu2-Ca, Y lengths had the largest and smallest values at 2-z=1.5. At this Tl content, Tc(zero) was the lowest of 108 K, and copper-apical oxygen (Cu2-O3) bond length was the smallest.