Deposition of epitaxial YBCO thin film on single domain YBCO substrate forthe development of RF components

The current trend of telecommunications has motivated an increasing need fo r an rf component of three-dimensional complex geometry in high-performance devices including tunable receivers, transformers, and inductors. In our p revious work we have developed a novel substrateless cavity using single do main YBCO. This cavity resonator has been demonstrated to exhibit a high Q value at the rf frequency. The surface resistance of the single domain YBCO Pt 77 K has reached a low value of 500 :Omega, comparable to those of thin films (200 :Omega). However, in single domain YBCO, the second phase Y2BaC uO5 (211) is unavoidable in the peritectic reaction, which can, if not well controlled, cause severe dissipative losses. To further reduce the surface resistance, we have deposited an YBCO thin film on the single domain YBCO substrate covering ad non-superconducting phases. The YBCO film and the sub strate will have the best lattice matching since they are the same species. To study the epitaxial growth mechanisms, we have also deposited the YBCO film on other types of substrates including YSZ. Experimental results on fi lm synthesis, interface structure, and superconducting properties will be r eported.