EFFECT OF LASER-BEAM PROFILE ON THE ABLATED HTS TARGET SURFACE

Laser ablated YBCO target surface has been investigated systematically to explore the effect of laser beam on the surface modification of th e target using scanning electron microscopy. The target surface is abl ated inhomogeniously due to erosion-resistant surface formed by surfac e segregation,which results in the surface modification, such as cones . The image of SEM shows the difference of cone formations at the boun dary and at the center of the ablated area on the target surface. This nonuniform modification of the ablated area is supposed to be mainly due to Gaussian profile of the laser beam and the difference of therma l conductivities of the ablated area.