TEMPERATURE-DEPENDENCE OF CRITICAL-CURRENT AND NORMAL-STATE RESISTANCE IN TL2BA2CACU2O8 BICRYSTAL JOSEPHSON-JUNCTIONS

The temperature dependence of the critical current I-c and the normal- state resistance R(n) for Tl2Ba2CaCu2O8 bicrystal Josephson junctions is discussed. At 77 K, the junction critical current density j(c) is 1 .3 x 10(4) A/cm(2), and the characteristic voltage I(c)R(n) is 0.1 mV. The maximum operating temperature T is about 90 K. Junctions are sta ble with respect to time, vacuum exposure and thermal cycling. The cri tical current decreases linearly with increasing temperature below abo ut 77 K, while R(n) is temperature-independent between 32 K and T. Th ese results indicate a strong influence of boundary resistance on the junction behavior and that the interface acts as an insulating barrier .