Raman Study of CeO2 Texture as a Buffer Layer in the CeO2/La2Zr2O7/Ni Architecture for Coated Conductors

The CeO2/La2ZrO7/Ni piled-up structure is a very, promising architecture for YBa2Cu3O7 (YBCO) coated conductors. We have grown YBCO/CeO2/LZO/Ni epitaxial structures by metalorganic decomposition (MOD) and metalorganic chemical vapor deposition (MOCVD) methods. The crystallographic quality of the CeO2 layer is not well determined by conventional X-ray diffraction (XRD) due to the superposition of LZO and CeO2 reflections. An alternative simple Raman spectroscopy analysis of the crystalline quality of the CeO2 films is proposed. The F-2g Raman mode of CeO2 can he quantified either by using two polarization configurations (crossed or parallel) or at two different rotation angles around the normal axis (0 degrees and 45 degrees) to obtain information about the sample texture. The sample texture call be determined via a quality, factor (referred to as the Raman intensity ratio, RIR) consisting of calculating the ratio of the integrated intensity, of the CeO2 F-2g mode at 0 degrees and 45 degrees in parallel polarization. This factor correlates with superconducting performance and the technique can he used as in on-line nondestructive characterization method.