YBA2CU3O7-DELTA CEO2 HETEROSTRUCTURES ON SAPPHIRE R-PLANE/

(001)YBa2Cu3O7-delta epitaxial films were prepared by laser ablation o n (1 (1) over bar 02)Al2O3 surface. A thin (001)CeO2 or (111)CeO2 buff er layer was deposited between the substrate and the superconductor fi lm to reduce their chemical interaction. In the initial stages of CeO2 buffer formation, its orientation depended strongly on the intensity of cerium ion interaction with oxygen. Epitaxial growth of (001)YBa2Cu 3O7-delta films was achieved both on (001)CeO2//(1 (1) over bar 02)Al2 O3 and (111)CeO2//(1 (1) over bar 02)Al2O3. The T-c temperature of epi taxial (001)YBa2Cu3O7-delta films was within 88-90 K, and the current J(c), at 77 K was in excess of 10(6) A/cm(-2). (C) 1998 American Insti tute of Physics.