MICRO-RAMAN STUDY OF LASER-ABLATED YBA2CU3O7-DELTA THIN-FILM DEPOSITED ON INCONEL WITH A TIN BUFFER LAYER

The Raman spectra of YBa2Cu3O7-delta superconducting thin film deposit ed on Inconel with a TiN buffer layer by a laser ablation technique ar e reported. The results indicate that the film is fully oxygenated, ho mogeneous and polycrystalline and has a preferred orientation along th e c-axis. No evidence of interdiffusion between the film and the subst rate was found. Unusual photoinduced changes in the Raman spectra were observed by varying the incident cw Ar+ (514.5 nm) laser power densit ies between 50 to 250+/-5 W mm-2. The increase in the intensity ratios of the out-of-phase and in-phase c-axis bending vibrations of O(2)-O( 3) oxygen atoms to that of the axial symmetric stretching vibration of bridging oxygen O(4) (i.e. I337/I503 and I445/I503) and the decrease in the full-width at half-maximum intensity (FWHM) of the out-of-phase , c-axis bending vibration (337 cm-1) can be attributed to the improve ment in the crystallinity of the film due to oxygen ordering in the Cu O2 planes induced by laser irradiation.