SURFACE-MORPHOLOGY, MICROSTRUCTURE AND ELECTRICAL-PROPERTIES OF Y-BA-CU-O THIN-FILMS

The relationship between the surface morphology, the microstructure an d the electrical properties of ''in situ'' YBCO thin films deposited b y off-axis magnetron sputtering has been investigated in a wide range of deposition temperatures, deposition rate and pressure of gas mixtur es. The Cu-rich surface particles formation observed in our experiment can be described using a classical thin film nucleation and growth mo del based on the concept of capture zones. The films with optimized el ectrical properties show high critical temperatures, T-c, up to 92 K a nd high critical current densities, J(c), up to 7.10(6) A/cm(2) and su rface microwave resistance, R-S, less than 0.6 mOhm (at 10 GHz) at 77K . The films with optimized surface smoothness show T-c up to 89 K, J(c ) up to 2.10(6) A/cm(2) and they are free of any particles down to a s ize scale of 100 Angstrom.