Fabrication of IBAD-MgO and PLD-CeO2 Layers for YBCO Coated Conductors**Supported by the ITER Project of the Ministry of Science and Technology of China under Grant No 2011GB113004, the Shanghai Commission of Science and Technology under Grant Nos 09DZ1206000 and 11DZ1100402, and the Youth Fund of Natural Science Foundation of China under Grant No 11204174.

Abstract

MgO thin films with different textures are fabricated by the ion beam assisted (IBAD) method on the Y2O3/Al2O3 buffered C276 tape. Then a CeO2 layer is directly grown on the IBAD-MgO film by the pulsed laser deposition (PLD) method. Effects of IBAD-MgO texture, substrate temperature and thickness on the grain alignment of the CeO2 layer are investigated. Film characterization is performed by x-ray diffraction and atomic force microscopy. It is found that the orientation and texture degree of the CeO2 layer are very sensitive to the IBAD-MgO texture. By optimizing the IBAD-MgO texture, CeO2 has pure (002) orientation and excellent biaxial texture deposited in a broad substrate temperature range. In addition, the PLD-CeO2 layer has a thickness effect. Under the optimized experimental condition, the PLD-CeO2 layer has a high in-plane texture of Δφ = 2.9° and a smooth surface with an rms surface roughness of less than 2 nm. The critical current density Jc of a 0.4-μm-thick YBCO film deposited on the CeO2 layer is 6.25 × 106 A/cm2 at 77K and a self-field.