Effect of La/Zr ratio in the precursor solution on the properties of La 2 Zr 2 O 7 and CeO 2 /La 2 Zr 2 O 7 films

La 2 Zr 2 O 7 (LZO) films and CeO 2 /LZO composite films were prepared on the biaxially textured NiW tapes using metal organic deposition method. Effect of molar ratio of La/Zr in the precursor solution on the texture and surface morphology of LZO films and composite CeO 2 /LZO films was investigated systemically. It was found that the content of lanthanum played an important role in the orientation control of the LZO film. Finally, the LZO film with ratio of La/Zr = 1.1/1 was obtained with the best properties as compared to others. And highly textured LZO-11 and CeO 2 /LZO-11 films with smooth surface were obtained on the NiW tape. YBa 2 Cu 3 O 7-x (YBCO) films with enhanced critical current density (J c ) were obtained on the optimized CeO 2 /LZO buffer layer. Graphical Abstract The LZO films were prepared from different LZO solutions with different molar ratio of La/Zr, and the effects of the La/Zr ratio on the texture and surface morphology of LZO films were systemically investigated. The results confirmed that the content of lanthanum in solution was closely related to the orientation control of the LZO film. When the ratio of La/Zr was smaller than La/Zr = 1, the pure (l00)-oriented phase was not achieved. When that was larger than La/Zr = 1.2, in spite of the pure (l00)-oriented phase, the more lanthanum content increased the lattice parameter of the LZO films. In summary, the ratio of La/Zr = 1.1 was the optimized ratio for the fabrication of LZO film due to the best texture and surface morphology.