EFFECTS OF Y2O3 PRECIPITATES ON CRITICAL CURRENT ANISOTROPY IN YBA2CU3O7-X THIN-FILMS PREPARED BY PLASMA-ENHANCED METALORGANIC VAPOR-DEPOSITION

Yttrium-rich YBa2CU3O7-x thin films containing yttria precipitates with an average size of less than 10 nm and with densities of up to 10(24)/m3 have been prepared by metalorganic chemical vapor deposition. The field dependence of the critical current density of the yttrium-rich films with the c-axis normal to the surface indicates that the precipitates act as effective pinning centers when the magnetic field is perpendicular to the CUO2 planes while their presence has no effect on the critical current density when the magnetic field is parallel to the CUO2 planes. In this case, intrinsic pinning of the weakly coupled CuO2 planes may be the dominant pinning mechanism in c-axis oriented YBa2CU3O7-x thin films.