COMPARISON OF YBA2CU3-XZNXO7 AND ER1-YPRYBA2CU3O7 SYSTEMS - RAMAN ANDXPS STUDIES

We report results of Raman and x-ray photoemission spectroscopy (XPS) measurements of the YBa2Cu3-xZnxO7 and Er1-yPryBa2Cu3O7 systems. No ap preciable changes were observed for YBa2Cu3-xZnxO7 in either measureme nt. On the other hand, Raman frequencies of Ba and apical oxygen (O(z) ) modes increase and the binding energies of Ba core levels show an in creasing trend as y increases in Er1-yPryBa2Cu3O7. Results for Er1-yPr yBa2Cu3O7 are consistent with our prevous work for Pr-doped 1:2:3 supe rconductors and van be explained in terms of hole localization at Ba s ites. Our experimental results indicate that the suppression mechanism in the YBa2Cu3-xZnxO7 system is different from that in the Er1-yPryBa 2Cu3O7 system.