Orientation mechanism of REBa/sub 2/Cu/sub 3/O/sub y/ (RE=Nd, Sm, Gd, Y, Yb) thin films prepared by pulsed laser deposition

The orientation behavior and mechanism of REBa/sub 2/Cu/sub 3/O/sub y/ (RE123) films have not been clarified yet. We prepared RE123 films by the pulsed laser deposition method and investigated the orientation behavior and mechanism. We argue that the orientation behavior strongly depends on thermodynamic parameters such as the heat of sublimation. The thickness and surface morphology dependences of the orientation suggest that c-axis oriented thicker films will be obtained in RE123 if the surface remains smooth up to objective thickness. Critical temperatures were around or higher than 90 K and critical current densities were larger than 1 MA/cm/sup 2/ for all RE123 films. From the viewpoint of the orientation, the Yb123 films were the easiest to grow with the c-axis normal to the substrate surface.