Properties of epitaxial YBa/sub 2/Cu/sub 3/O/sub y/ thin films on sapphire with PrBa/sub 2/Cu/sub 3/O/sub y/ buffer layers

YBa/sub 2/Cu/sub 3/O/sub y/ epitaxial thin films have been grown on a PrBa/sub 2/Cu/sub 3/O/sub y/ layer deposited on a sapphire substrate, using XeCl excimer laser ablation for both depositions. The films were deposited in situ by means of a rotating multitarget system carrying the two targets. The substrate holder was heated by a CO/sub 2/ 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. DC transport critical current densities for YBa/sub 2/Cu/sub 3/O/sub y/ grown on PrBa/sub 2/Cu/sub 3/O/sub y//Al/sub 2/O/sub 3/ have been measured as a function of the temperature and an applied magnetic field.<
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