Optimized double sided DyBa2Cu3O7-thin films for RF applications

DyBa2Cu3O7-thin films (DyBCO) prepared by thermal co-evaporation are an attractive alternative to YBCO for the use in RF devices. Large area, double sided DyBCO films have been grown on LaAIO3 and MgO substrates which are frequently used for RF filter designs. Due to an enhanced transition temperature Tc of 90 K compared to YBCO (typical 88 K), at 77 K DyBCO films exhibit an about 20'% lower surface resistance than YBCO, while the power handling capability is comparable. Beyond that, DyBCO films are chemically much more stable and under humid conditions and the long-term degradation behavior is greatly improved.