Effect of PrBa₂Cu₃O_7-x buffer layer thickness on the properties of YBa₂Cu₃O_7-x thin films grown on sapphire by laser ablation

Superconducting YBa₂Cu₃O_7-x (YBCO) thin films were deposited on r-plane Al₂O₃ substrates with PrBa₂Cu₃O_7-x (PBCO) buffer layer by XeCl excimer laser ablation. The thickness of PBCO buffer layer was systematically changed to investigate the superconducting properties of YBCO thin films on sapphire. The structure and surface morphology of the films were characterized by X-ray diffraction and scanning electron microscopy (SEM). Superconducting transition temperatures were varied depending on the buffer layer thickness. Interdiffusion between laser-ablated YBCO thin films and Al₂O₃ substrates had been studied by Auger electron spectroscopy (AES). The results of this study show that diffusion does not occur between the YBCO thin film and the substrate even with 20 Å thick PBCO buffer layer.