RAMAN MICROPROBE TECHNIQUE DIAGNOSTIC OF YBCO FILMS PRODUCED BY LASER-ABLATION

We have used a Raman microprobe technique for the characterisation and the diagnostic of YBCO superconducting thin films deposited by Pulsed -Laser Ablation (PLA) on MgO insulating substrates. Using polarisation analysis associated with sample rotations we developed a method for f ilms orientation determination without any request for absolute calibr ation of the Raman spectra. The use of a bidimensional multichannel de tector (OMA 4) allowed an overall detection time of 40 minutes. Each s pectrum (shift range from 100 cm(-1) to 700 cm(-1)) takes about 600 se conds. The results of this detection were used to determine the oxygen content, from the position of the Raman mode at 500 cm(-1). Homogenei ty was checked with the spatial resolution allowed by the dimension of the focused laser beam (10 mu m).