GROWTH MODE OF CU-RICH PARTICLES ON LASER-ABLATED YBA2CU3O7 THIN-FILMS

The microstructure of the laser-ablated YBa2Cu3O7 (YBCO) thin film dep osited on heated (100) SrTiO3 substrate was examined by transmission e lectron microscope. The particles on the film mainly consist of CuO an d few CuYO2. Most of these non-superconducting particles nucleate on o r near the surface of the film and protrude about 100-400 nm in height . A large amount of alpha-axis YBCO grains also exist in the film, whi ch nucleate at the substrate surface and grow perpendicularly above th e c-axis YBCO film. The YBCO thin film deposited under law oxygen pres sure has very different microstructure compared with YBCO thin film de posited under high oxygen pressure.