(Batio3)m(Gd,Ce)3 Cu2O7: a new homologous series of layered cuprates containing various layers of perovskite units

Abstract

Two compounds in a new homologous series (BaTiO₃)_m(Gd, Ce)₃ Cu₂O₇ with m= 2 and 3 have been synthesized and characterized. The tetragonal unit-cell parameters, a= 3.874 04(4)Å, c= 36.888(1)Å(for m= 2) and a= 3.881 45(5)Å, c= 44.775(1)Å(for m= 3) for the two compounds were determined by X-ray and electron diffraction. From the diffraction patterns, we deduce that the structures of the two compounds are built up by alternative stacking of multiple perovskite layers, copper–oxygen planes and double fluorite layers. The unusual structural characteristics in the series are the wide separations between the CuO₅ planes. Although both compounds contain CuO₅ planes, as is common in high-T_ccuprates, we have not yet succeeded in making the samples superconducting.