Five superconductors of the Nd1 + xBa2−xCu3O6.5 ± y type (x = 0.00, 0.05, 0.10, 0.15, and 0.20) are prepared. The orthorhombic crystal lattice observed at x = 0 gradually transforms into a tetragonal structure at increasing values of x. Resistivity measurements (dc) show a metal‐semiconductor type transition at temperatures above Tc. Tc ranges from 92 to 72 K by increasing values of x from 0.00 to 0.20, respectively. The oxygen content (y) increases with increasing x. Comparison of calculated and experimental values of y suggests that Nd is present in the form of Nd2O3. In contrast to earlier reports, it appears that the behavior observed are due to a mixture of Nd2O3 and NdBa2Cu3O6.5 ± y instead of Nd1 + xBa2‐xCu3O6.5 ± y suggested earlier.

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