We have compared nonsuperconducting and superconducting ceramic samples of RuSr2Eu1.5Ce0.5Cu2O10 prepared by a polymerizable complex method using Raman spectroscopy and electron diffraction. The superconductivity in these ruthenocuprate samples was associated with ruthenium deficiency. It turned out that superconducting samples contain an epitaxial satellite phase having lattice parameters of a = 3.8407Å, c = 11.417Å (a/c ≈ 3), whereas Raman spectra revealed the presence of carbonate groups, which coordinate metal ions in a manner similar to that in the superconducting carboxycuprates. Therefore, we speculate that the satellite phase is EuSr2Cu3-x(CO 3)xO7+z doped with Ru into Cu chain site and it might be responsible for superconductivity. The intergrowth of such a phase was confirmed by HREM.
ASJC Scopus subject areas