W. Widder et al., THE BEHAVIOR OF THE INTERGRANULAR CRITICAL-CURRENT DENSITY OF POLYCRYSTALLINE, C-AXIS ORIENTED YBA2CU3O7-DELTA FILMS, Czechoslovak journal of Physics, 46, 1996, pp. 1287-1288
The intergranular critical current density j(cJ)(T) of polycrystalline
, c-axis oriented YBa2Cu3O7-delta thin films was determined at zero DC
magnetic field by isothermal AC susceptibility measurements chi(h(AC)
) The shift of the intergrain peak in chi ''(h(AC)) to lower field amp
litudes with increasing temperature was used to determine the temperat
ure dependence of j(cJ). The obtained behaviour was confirmed by trans
port critical current measurements which have been performed under sel
f-field conditions. We compare our experimental data with a model for
Josephson tunneling between superconducting grains in which the superc
onducting order parameter has d-wave symmetry.