2-PHASE INTERGROWTH IN BI2SR2CA0.6Y0.4CU2OY SINGLE-CRYSTALS

In Bi2Sr2Ca0.6Y0.4Cu2Oy single crystals we have identified the intergr owth of two phases; a normal Bi2Sr2CaCu2Oy type phase with a 4.6b modu lation period and a secondary,phase with a 9.4b modulation period. Bot h the two phases have orthorhombic basic structures with similar latti ce parameters but different symmetries, i.e. Bbmb for the normal phase and Ccca for the secondary phase. The c-parameters of these two phase s are found to vary independently upon changing the nominal Y content. The modulation characteristics of the secondary phase implies a close structural relation between the two phases. Both phases are discussed from a structural and a compositional point of view.