(Nd, Eu, Gd)-Ba-Cu-O superconductors with combined addition of CeO2 and Pt

A combination of CeO2 and Pt doping has been performed for oxygen-controlle d melt-growth processed (Nd, Eu, Gd)-Ba-Cu-O with the aim of refining the ( Nd, Eu, Gd)(2)BaCuO5 particles, which were added to the (Nd, Eu, Gd)Ba2Cu3O y (NEG-123) precursor. Observations using transmission electron microscopy demonstrate that sub-micrometre-sized 211 particles could be embedded succe ssfully in the NEG-123 matrix. Energy dispersive x-ray analysis (EDX) confi rmed that these sub-micrometre-sized 211 particles consisted mainly of Eu o n the rare earth site for the samples containing 10 mol% (Nd, Eu, Gd)(2)BaC uO5. As a result, the (Nd, Eu, Gd)-Ba-Cu-O sample with a combined addition of CeO2 and Pt exhibits an enhanced fishtail effect with a critical current density, J(c), of 73 000 A cm(-2) at 3 T for fields parallel to the c-axis at 77 K.