Enhanced superconducting properties in MOD-YBCO thick films with CeO2 interlayer

In YBa2Cu3O7-x (YBCO) film there exists thickness effect: the critical current density of YBCO film drops precipitously as the coating thickness increases, especially in the case that the thickness of YBCO film exceeds 1 m. In this paper, we introduce very thin layers of CeO2 into YBCO layers and successfully fabricate the structure of YBCO/YBCO/CeO2/YBCO superconducting thick film. Firstly, YBCO films with two layers are fabricated on a LaAlO3 substrate by a multiple coatings process using a trifluoroacetate metal organic deposition method. Secondly, CeO2 thin films are deposited on YBCO films by RF-sputtering. Finally, we prepare the third YBCO film on CeO2interlayer. No cracks are observed in scanning electron microscopy images of these films; further, the majority of the grains in the films are well-textured and c-axis oriented. The full-width-half-maximum of the out-of-plane texture is measured to be 1.395 for the multilayer YBCO film at a thickness of 2 m Using this multilayer technology, we achieve Jc values of up to 1.36 MA/cm2 (77 K, self-field) in films as thick as 2 m, for an extrapolated critical current of 272 A/cm. We attribute the enhanced performance of the thick YBCO film to the CeO2 interlayer which playsan important role in transmission texture and stress relaxation.