The plasma-assisted laser deposition (PLD) technique has produced high critical temperature and current films of high Tc superconducting materials at 400C. This is the lowest process temperature ever reported for these materials for any in situ method. The PI will investigate the oxygen stoichiometry and its relationship to the substrate temperature and the "effective" oxygen energy flux from plasma to film during growth process. This will be followed by a careful study of the film/substrate interaction, including the effects of diffusion barrier layers. The effects of crystalline grain size, mechanical stress, and metallic-coating encapsulation on the critical current will be investigated.