Application of Raman spectrometry for the characterization of complex oxide thin films grown by MOCVD

Abstract
Thin epitaxial films of complex oxide materials including superconductors RBa₂Cu₃O_7-δ (R=Ho,Lu), CMR manganites R_1-xA_xMnO₃ (R = La, Pr, Nd ; A = Ca, Sr), conducting perovskites La_0.5Sr_0.5CoO₃-LaNiO₃ were prepared by aerosol and flash MOCVD. The application of Raman spectrometry was found to be an unique possibility for a non-destructive control of the oxygen content of the material in films (including the analysis of the oxygen isotope content) and the appearance of secondary phases. In particular cases, the phase analysis can be carried out for very small amounts of impurity phase exceeding the detection limit provided by other techniques, such as X-ray diffraction or EDX element analysis. Advances in the measurement technique have expanded facilities of Raman spectrometry to the analysis of perovskite thin films with only minor deviations from a cubic symmetry. As a result, delicate variations of the structure with the composition of thin film perovskite-like solid solutions were studied.