COPLANAR WAVE-GUIDE AND EPITAXIAL YBA2CU3O7-X NDALO3/YBA2CU3O7-X- TRILAYER TRANSMISSION-LINE RESONATORS FOR MICROWAVE APPLICATIONS/

High quality YBa2Cu3O7-x (YBCO) thin films were grown on LaAlO3 by dc- magnetron sputtering. The films showed critical temperatures of 91 K a nd critical current densities well beyond 106 A/cm2 at 77 K. From 200 nm thick films coplanar waveguide resonators were patterned with chara cteristic impedances between 40 and 50 OMEGA. At 77 K the highest unlo aded quality factors reached values up to 1200 at 6.2 GHz measured at an input power of 10 dBm. This results in an attenuation constant of 1 .8 dB/m of the transmission line. From these measurements the surface resistances R(S) and the magnetic penetration depths lambda(L) were ev aluated. The lowest R(s) value was 105 muOMEGA at 77 K and at 6.2 GHz. The smallest magnetic penetration depth lambda(L)(0) was 160 nm. Addi tionally, for the first time trilayer structures with a dielectric thi ckness of 400 nm and 800 nm respectively were patterned into microstri p resonators. At 50 K we measured a quality factor of 85 at 4.7 GHz re sulting in an attenuation of 26 dB/m and a surface resistance R(s) of 340 muOMEGA. For thick dielectrics the upper YBCO films already contai ned significant portions of polycrystalline material.