HIGH-CURRENT PRESSURE CONTACTS TO AG PADS ON THIN-FILM SUPERCONDUCTORS

High current, low resistance, nonmagnetic, and nondestructive pressure contacts to Ag pads on YBa2Cu3O7-delta (YBCO) thin film superconductors were developed in this study. The contact resistance reported here includes the resistance of the current lead/Ag pad interface, the Ag pad/YBCO interface, and the bulk resistance of the contact material. This total contact resistance is the relevant parameter which determines power dissipation during critical-current measurements. It was found that regardless of the optimization of the Ag pad/YBCO interface through annealing, a pressure contact can yield a lower total resistance than a soldered contact. The lowest resistance obtained with pressure contacts was 3 mu Omega (for a 2 x 4 mm(2) contact). These contacts may be useful for many different high temperature superconductor (BTS) studies where high-current contacts with low heating are needed.