| Second-generation YBCO high temperature superconductor(HTS) tapes has attracted much attention due to its high irreversibility fields, lower ac loses, better in-field performance, and lower processing costs. The main difficulties in fabricating coated conductors are lattice mismatch and the diffusion of oxygen and metal atoms. So it is necessary to depositing buffer layers between flexible metal substrates and YBCO layer. MOD method is easy to control, low cost, easy to advantages such as large-scale production. STO thin films were grown on biaxial textured Ni-5at%W alloy with MOD method for further directly deposition HTS film on this buffer layer and structure and surface morphology of buffer layer thin films was study.In this paper, process parameters of preparation the STO films with MOD were studied. The effects of the annealing temperature, heating rate, spinning rate on structure and surface morphology were investigated. We obtained STO thin films with (200) single orientation, surface roughness (RMS = 3.6nm), good repeatability by optimizing the process parameters, in the spinning rate of 2000-3000r/min using rapid thermal annealing at 975℃.In addition, in order to study the feasibility of all-MOD preparation the second-generation high-temperature superconductor tapes, we have also carried out in TFA-MOD method preparation YBCO superconducting thin films on STO buffer layer. Good c-axis oriented YBCO thin films were prepared in an low O2 atmosphere at 780℃. Experimental proof of the STO single buffer layer can effectively prevent the YBCO superconducting layer and the metal substrate inter-diffusion, and can transfer with the substrate texture.Finally, Nb doped STO thin films were studied. The effects of the different dopant concentration on the film texture, surface morphology and electrical conductivity properties were investigated. Without prejudice to texture of thin films and surface morphology, to produce STO film with some conductive properties. |
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