Effect of incorporation of Sb in place of Bi in the bismuth cuprate superconductors has been examined. The nominal compositions studied are MCa1·5Sr1·5Cu2O8+δ and MCa2Sr2Cu3O10+δ, whereM=Bi2−xSbx or Bi1·5−xSbxPb0·5. Different preparative routes such as the ceramic method, the matrix route as well as the melt route were employed to prepare the materials. No indication of either Sb entering the lattice or enhancement ofTc is noted from resistivity, magnetic susceptibility and microwave absorption measurements.
