Effect of chemical inhomogeneity in bismuth-based copper oxide superconductors
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چکیده
We examine the effect on the superconducting transition temperature (Tc) of chemical inhomogeneities in Bi2Sr2CuO61d and Bi2Sr2CaCu2O81d single crystals. Cation disorder at the Sr crystallographic site is inherent in these materials and strongly affects the value of Tc . Partial substitution of Sr by Ln ~Ln 5 La, Pr, Nd, Sm, Eu, Gd, and Bi! in Bi2Sr1.6Ln0.4CuO61d results in a monotonic decrease of Tc with increasing ionic radius mismatch. By minimizing Sr site disorder at the expense of Ca site disorder, we demonstrate that the Tc of Bi2Sr2CaCu2O81d can be increased to 96 K. Based on these results we discuss the effects of chemical inhomogeneity in other bulk high-temperature superconductors.
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تاریخ انتشار 2004