FLUX-PINNING ENHANCEMENT IN MELT-PROCESSED YBA2CU3O7-DELTA THROUGH RARE-EARTH ION (ND, LA) SUBSTITUTIONS

Stoichiometric YBa2Cu3O7-delta (Y123) samples doped with excess Nd2O3 and La2O3 additions were melt processed in air. Because decomposition and reformation of 123 occurs during melt processing, Lighter rare-ear th ion substitution in 123 takes place. As the lighter rare-earth ion sizes (Nd, La) are comparable to that of Ba2+, in addition to Y ion si te substitution, partial substitution into the Ba2+ sites is also anti cipated. The T-c and magnetic properties of lighter rare-earth oxide d oped samples were analyzed and compared with undoped Y123 to investiga te the flux pinning enhancement due to these substitutions. The lighte r rare-earth oxide doped, melt processed 123 shows significant improve ment in magnetization compared to undoped samples, which is likely due to point defects created by partial substitutions of the lighter rare -earth ions. (C) 1995 American Institute of Physics.