MORPHOLOGICAL-STUDY OF YBA2CU3OY THIN-FILMS GROWN BY EXCIMER-LASER ABLATION METHOD

A close correlation between the YBx(2)Cu(3)O(y) film morphology and lo cation of the (100) MgO substrate during growth by excimer laser ablat ion was obtained. When the substrate was placed inside the fringe port ion of the laser plume, the spiral shape was most clearly seen on the entire film surface for bath the conventional and eclipse ablation met hods. When the substrate was placed outside the plume, the spiral grow th was less pronounced. On the other hand, when the substrate was plac ed inside the plume core, marked deformation of the morphology occurre d, and the superconducting critical temperature was lowered. This corr elation was explained to some extent by the spatial variation of kinet ic energy of the flying growth species.