Composition dependences of T-c, J(c), physical property and crystal structure of Bi1.8Pb0.3Sr2.0Ca0.9Y0.1Cu2.0-xMxOy (M = Zr, Zn) superconducting oxide

作者：Idemoto Yasushi^*; Sekizawa Oki; Kitamura Naoto

来源：Physica C-Superconductivity and Its Applications, 2011, 471(5-6): 205-212.

DOI：10.1016/j.physc.2010.12.017

• High T-c superconducting oxides
• Bi-2212 based material
• Substitution effect
• Neutron diffraction

In this study, we focused on bulks and thin films of Bi1.8Pb0.3Sr2.0Ca0.9Y0.1Cu2.0Oy, and replaced Cu by Zr4+ and Zn2+. From the electrical conductivity measurements on the bulk samples, it was found that T, became higher by a partial substitution of Zr4+, and exhibited a maximum value in the sample with the Zr4+ content of 0.05. On the other hand, T-c was decreased by the Zn2+ substitution. These results suggested that it was possible to control a carrier concentration by the Zr- and Zn-substitutions. Indeed, an average valence of the Cu, determined by a chelate titration, was changed by these substitutions. Similar tendency of the superconducting properties was also observed in the case of the film samples. In order to investigate crystal structures in detail, we measured neutron diffraction patterns, and then performed the Rietveld analysis. As a result, it was clarified that the (Cu, Zr)-O2 layers became flat by the Zr-substitution. Such a structure change may be one of the reasons why the substitution improved the superconducting properties.

• 出版日期2011-3