Effect of doping on the structure and property of YBa2Cu3O7-δ ceramics

There has been considerable recent work on improving the electrophysical properties of YBa2Cu3O7-δ high-temperature superconductor ceramics. One approach to this problem entails additional doping of the ceramics. In the present work, the authors studied the effect of substituting Group I-III element ions into the cation sublattice of YBa2Cu3O7-δ ceramics on its structure and electrophysical properties. Silver was used for the partial replacement of copper (0.033, 0.16, and 0.33 atom fractions) (YBa2Cu2.9Ag0.1O7-δ, YBa2Cu2AgO7-δ, respectively). Strontium was used to replace barium (0.05, 0.25, and 0.5 atom fractions; YBa1.9Sr0.1Cu3O7-δ, YBa1.5Sr0.5Cu2O7-δ, and YBaSrCu3O7-δ, respectively). Lanthanum was used to replace yttrium (0.1, 0.5, and 1 atom fraction; Y0.9La0.1Ba2Cu3O7-δ, Y0.5La0.5Ba2Cu3O7-δ, and LaBa2Cu3O7-δ, respectively). These elements were selected in light of the similarity of the structure of their outer electron shells although their ionic radii are rather different from the radii of the substituted ions