UV laser beam/YBCO target interaction for optimum preablation for the growth of YBCO thin films

Abstract

The morphological and compositional changes which take place during the laser irradiation of YBCO targets are discussed. The understanding of the evolution of target composition, will lead to better control of film quality. In the case stated here, a XeCl excimer laser was used to irradiate rotated and also non-rotated YBa2Cu3O7-x targets. The modified surface of these targets was systematically studied by scanning electron microscopy and energy dispersive x-ray microanalysis. It was observed that some crucial deposition parameters, such as the number of pulses and fluence has a strong effect on the roughening of the target. A comparative study was done on the derived High-Tc superconducting thin films. It was shown that the conditions during the preablation procedure which affect the target surface morphology correlate closely with the appearance of laser droplets on the film surface.