Zaremba O. Synthesis and crystal structure of compounds of the homologous series M2Cu2O3-CuO2 (M = Ca, Sr, Pb, Bi)

The influence of a partial substitution of the components on the formation and incommensurate structure of (Ca6Sr8)Cu24O41, a representative of the homologous series [M2Cu2O3]m[CuO2]n with m/n = 7/10, was investigated by X-ray diffraction. The Ca/Sr atoms were partly replaced by atoms of a p-element of the group III-V of the periodic system (Bi, Pb, Sb, Sn, In, Ge, Ga), Y, or rare-earth metal (Gd, Dy, Er, Yb) atoms, and Cu atoms by Co or Ni atoms. The crystal structure of another representative of the [M2Cu2O3]m[CuO2]n series, (Ca0.59Sr0.39Bi0.02)10Cu17O29 with m/n = 5/7 was determined by single-crystal X-ray diffraction. The synthesis of polycrystalline samples by solid-state reaction was optimized and an alternative method for the synthesis of layered cuprates by oxidation of intermetallics was proposed. For this purpose the interaction of the components in the Sr-Y-Cu and Sr-Cu-Bi ternary systems was studied and phase equilibria were established. The existence of the ternary compound SrCuBi was confirmed, and the formation of a solid solution (Sr1-xYx)Cu5 was observed. Studies of the temperature and field dependences of the magnetic susceptibility of (Ca,Sr,Y)14Cu24O41 compounds with different yttrium content showed paramagnetic properties at temperatures above the boiling temperature of nitrogen. The magnetic susceptibility increases with increasing yttrium content.