Depth profiling Raman spectroscopy of a thin YBa2Cu3O7 − δ film

High spectral (1.5 cm− 1) and spatial (~ 1000 nm lateral and vertical) resolution Raman spectra taken at room temperature in the depth of a thin (350 nm) YBCO film with good superconducting properties are presented and discussed. The differences between Raman spectra corresponding to different depths in the film are interpreted as depth-dependant changes in the film's structure, degree of oxygenation, and superconducting properties. These changes are in agreement to what we expect from a film obtained by pulsed laser deposition technique. The resonance of the most significant Raman shift (500 cm− 1), monitoring the oxygen content of YBCO films, for 488 nm excitation light, was used to overcome the relatively small penetration depth of visible light in YBCO (~ 200 nm). We found the range of parameters for the depth profiling Raman system such as to obtain the maximum signal intensity and a reasonable number of distinctive Raman spectra corresponding to different depths of the YBCO film.