Ag screen contacts to sintered YBa2Cu3Ox powder for rapid superconductor characterization

The authors have developed a method for making current contacts and voltage taps to YBa₂Cu₃O_x sintered pellets for rapid superconductor characterization. Ag wire screens are interleaved between calcined powder sections and then fired at 930°C to form a composite pellet for resistivity and critical current measurements. The Ag diffuses into the powder during the sintering process forming a proximity contact that is permeable to O₂. Contact surface resistivities (area-resistance product) range from 1 to 10 μΩ-cm² at 77 K for the Ag-powder interface. In this configuration, current can be uniformly injected into the ends of the pellet through the bonded Ag screen electrodes. Ag screen voltage contacts, which span a cross section of the pellet, may provide an ideal geometry for detecting voltage drops along the pellet, minimizing current transfer effects