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

The CeO2/La2Zr2O7/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 F2g Raman mode of CeO2 can be quantified either by using two polarization configurations (crossed or parallel) or at two different rotation angles around the normal axis (0° and 45°) to obtain information about the sample texture. The sample texture can 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 F2g mode at 0° and 45° in parallel polarization. This factor correlates with superconducting performance and the technique can be used as an on-line nondestructive characterization method.