Surface resistance of screen-printed Bi2223 thick films on Ag and dielectric ceramic substrates

Surface resistance R-s of screen-printed (Bi,Pb)(2)Sr2Ca2Cu3Ox thick films on Ag, MgO, and Ba(Sn,Mg,Ta)O-3 substrates was measured at 10.7 GHz in the temperature range between 20 and 130 K using a dielectric resonator method. For thick films on Ag substrates, it becomes lower than that for a Cu plat e as temperature decreases below 100 Ii, and reaches 1.7 m Omega at 77 K an d 0.3 m Omega at 30 K. The use of MgO or Ba(Sn,Mg,Ta)O-3 dielectric substra te for film fabrication causes some degradation in the value of R-s, while still being superior to that for a Cu plate below 80 K. From a practical po int of view, the (Bi,Pb)(2)Sr2Ca2Cu3Ox thick films were screen-printed on b oth sides of Ba(Sn,Mg,Ta)O-3 disk to serve as superconducting electrodes fo r the dielectric resonator. The unloaded quality factor Q(u) for the resona tor at 2.1 GHz on a TM010 mode is superior to the same dielectric resonator with Cu electrodes below 90 Ii. It is 3 times higher than the value for th e resonator with Cu electrodes at 70 Ii and also 5 times higher at 30 I;.