MECANISM DE CREŞTERE ŞI PROPRIETĂŢI ALE FILMELOR SUBTIRI DE YBa2Cu3O7-δ DEPUSE PRIN ABLAŢIE LASER PE (001 ) srTiO3

High quality, single phase c-axis oriented YBa 2 Cu 3 O 7-δ thin films with superconducting properties were grown by laser ablation on (001) SrTi0 3 substrates. The surface morphology of the films has been investigated by means of high-pressure reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), and scanning electron microscopy (SEM), while the structural properties were studied by X-ray diffraction (XRD). Deposition under optimum conditions produces films with relatively smooth surface, with a roughness of about 10-15 nm, as confirmed by AFM and SEM data. The growth follows a Stransky-Krastanov mechanism governed by the substrate-film interface properties due to presence of epitaxial strain. The films show good superconducting properties with T c values of 85-91 K. Results on the fabrication and electrical transport properties of ramp-type Josephson junctions with YBa 2 Cu 3 O 7-δ electrodes and PrBa 2 Cu 3 O 7-δ barrier are presented.