CHARACTERISTICS OF BICRYSTAL-TYPE JOSEPHSON-JUNCTIONS OF YBA2(CU1-XNIX)(3)O-7-DELTA FILMS

We report the successful fabrication and characterization of the bicrystal-type Josephson junctions of YBa2(Cu1-xNix)(3)O-7-delta epitaxial thin films. Both T-c and I(c)R(n) products decrease with doping Ni, while the ratio, d(T-c)/d(I(c)R(n)), is almost constant. The normal resistance of the junction (R(n)) increases with resistivity in the normal state (rho(c)) of the electrode material. R(n)(5 K) for x approximate to 10% is similar to 9 times as high as that for x = 0%, while rho(n)(250 K) for x = 10% is similar to 3.8 times as high as that for x = 0%. The correspondent relation between R(n) and rho(n) indicates that the barrier layer at the grain boundary consists of the same system as electrode superconductor. The increase of R(n) is explained by the decrease of carrier mobility.