Two phase co-existence in YBa(CuCo)O superconductor with x=0.03

Co-doped impurity-free YBa(CuCo)O(123Co) with x=0.03 superconducting samples have been synthesized using conventional solid state reaction techniques. A Rietveld analysis of X-ray diffraction data for these specimens reveals that two structures (one tetragonal represented by T-YBCO, and the other orthorhombic represented by O-YBCO) co-exist at this composition of the cuprate. The use of a single tetragonal or single orthorhombic structure as the model for the refinements does not produce acceptable fits to the X-ray diffraction pattern. The refinements show that the T-YBCO phase at 298 K has tetragonal symmetry () with =0.387879(4) nm, =1.17314(1) nm, and that the O-YBCO phase has at 298 K an orthorhombic symmetry () with =0.387555(4) nm, =0.389400(4) nm, =1.17363(1) nm, respectively.