Microstructures of YBa_2Cu_3O_7 films prepared by magnetron sputtering on Al_2O_3 substrate with a CeO_2 buffer layer

摘要

High-T_c superconducting YBa_2Cu_3O_7 films with a CeO_2 buffer layer, deposited onto sapphire substrates, were prepared by off-axis rf-niagnetron sputtering. It is found that the microstructure of the buffer layer can be controlled by the substrate temperature, and is connected with the formation of the discontinuities in the film, which are the origin of micropores. The microstructural peculiarities of the YBa_2Cu_3O_7/CeO_2/Al_2O_3 films are studied and discussed.