Ag screen contacts to sintered YBa/sub 2/Cu/sub 3/O/sub x/ powder for rapid superconductor characterization

The authors have developed a method for making current contacts and voltage taps to YBa/sub 2/Cu/sub 3/O/sub x/ sintered pellets for rapid superconductor characterization. Ag wire screens are interleaved between calcined powder sections and then fired at 930 degrees 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 O/sub 2/. Contact surface resistivities (area-resistance product) range from 1 to 10 mu Omega -cm/sup 2/ 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.<
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