We report on the successful synthesis of single-phase Zr-substituted Y
Ba2(Cu1-xZrx)3O7-delta superconductors up to 5 at.% (x = 0.0-0.05) and
characterized them according to resistivity and ac susceptibility mea
surements. We did not observe any significant change in orthorhombicit
y and in T(c) similar to Ni2+- and Nb5+-doped systems.