Microstructure and Properties of Y-123/Y-211 Bulk Superconductors with BaCeO3 and BaO2 Addition

YBa2Cu3O7−δ (YBCO) bulk single-grain superconductors were prepared by a TSMG process. CeO2, BaCeO3 and BaO2 powders were added to nominal composition Y1.5Ba2Cu3O7 with the aim to refine Y2BaCuO5 (Y-211) secondary particles. Added powders were refined by milling in a friction milling and characterized by X-ray powder difractometry. Thermal properties of the systems were characterized by DTA. Microstructure of samples was studied by PLM. Successful refinement of Y-211 particles size was confirmed by IP measurements. Transition temperatures and field dependences of the magnetic moment for further determination of the critical current densities were obtained using a VSM