JOSEPHSON CHARACTERISTICS IN A-AXIS ORIENTED YBA2CU3O7-DELTA/PRBA2CU3O7-DELTA'/YBA2CU3O7-DELTA JUNCTIONS

A sandwich-type all-oxide Josephson junction consisting of an a-axis oriented YBa2Cu3O7-delta/PrBa2Cu3O7-delta'/YBa2Cu3O7-delta structure has been realized and its Josephson characteristics experimentally investigated. Almost all the fabricated junctions showed the Josephson characteristics, including a resistively shunted junction (RSJ)-like current-voltage characteristic and a Fraunhofer-like magnetic-field dependence of the critical current. The obtained maximum values of the critical-current density j(c) and the I(c)R(n) value were 110 A/cm2 and 80-mu-V, respectively, for a 50-nm-thick PBCO interlayer at 3 K. Besides, the temperature dependencies of the critical current and the normal resistance were measured. I(c) was proportional to exp(- aT1/2), where a is a constant.