Is LaAlO3 a viable substrate for the deposition of high quality thin films of YBa2Cu3O7-δ?

A-systematic study of the surface morphology of epitaxial thin films of YBa2Cu3O7-delta on (100) LaAlO3 wafers is reported. The films were prepared by high pressure dc sputtering or laser ablation deposition, on wafers of 0.5-w.8 min thickness and 2 or 3 inch diameter. Optical and atomic force microscopy (AFM) were used to characterize the surfaces, while transport was used to verify the high quality of the films. For films prepared under the same condition's, we found a systematic increase in size and number of extended defects in the films with wafer thickness. In some cases, a clear correlation was observed between the defect structure and the twin boundaries of the LaAlO3 substrate. We specify the conditions for: minimizing these defects.