PROPERTIES OF EPITAXIAL YBa2Cu3Oy THIN FILMS ON SAPPHIRE WITH PrBa2Cu3Oy BUFFER LAYERS

We have grown YBa2Cu3Oy epitaxial thin films on a PrBa2Cu3Oy layer deposited on a sapphire substrate. The laser ablation technique with an XeCl excimer laser was used for both depositions. The films were deposited in situ by means of a rotating multi-target system carrying the two targets. The substrate holder was heated by a CO2 laser beam. The as deposited films show a zero resistance critical temperature of 87 K and a high degree of epitaxiality with c-axis orientation. The samples have been patterned in the shape of strips of variable width between 10 mu m and 30 mu m. D. C. transport critical current densities of YBa(2)Cu(3)Oy grown on PrBa(2)Cu(3)Oy/Al2O3 have been measured as a function of the temperature and an applied magnetic field.