Influence of combined Pt and CeO₂ additions on microstructure and magnetic properties in (Nd, Eu, Gd)-Ba-Cu-O

We studied the effect of the combined addition of Pt and CeO₂ on the dispersion of secondary phase Gd₂BaCuO₅ (Gd-211) particles in melt-processed (Nd_0.33Eu_0.33Gd_0.33)Ba₂Cu ₃O_y (NEG-123) by varying the CeO₂ content from 0 to 3%. Scanning electron microscopy revealed that submicrometre-sized Gd-211 particles were distributed uniformly throughout the NEG-123 matrix for additions of up to 2 mol% CeO₂. The critical current density (J_c) increased with increasing CeO₂ content, particularly at low magnetic fields. The zero-field J_c value reached its maximum of 100 kA cm^-2 at 77 K for 1 mol% CeO₂. An improvement in low-field J_c was attributed to the refinement of Gd-211 particles.