Due to the current necessity to obtain epitaxial superconductor films at low cost, we report the growth of YBa2Cu3O7 (Y123) films by chemical deposition. The procedure involved simple steps such as precipitation of stoichiometric amounts of yttrium, barium and copper acetates in oxalic acid (H2C2O4). The precursor solution was dripped onto LaAlO3 (100) substrates with the help of a Fisher pipette. The films were annealed in oxygen atmosphere during 12 h at three different temperatures: 820 °C, 840 °C and 860 °C. After 820 °C and 860 °C annealing, X-ray diffraction (XRD) analysis revealed high intensity of the (00l) reflections denoting that most of the Y123 grains were c-axis oriented. In addition, we also observed a-axis oriented grains ((h00) reflexion), minor randomly oriented grains and other phases (such as Y2BaCuO5 and CuO). In contrast, the sample treated at 840 °C, we noticed c - And a-axis oriented grains, very small amounts of randomly oriented grains without formation of other phases. From the magnetization versus temperature measurements, the critical temperatures were estimated at 70K and 90K for the samples annealed at 820 °C and 860 °C respectively.
Bibliographical noteFunding Information:
ABD is grateful to CSI-VRI-UNMSM for funding the project No 101301071. The work in Cambridge was supported by the European Union program ALBAN (Contract No. E06D101257PE) and the Cambridge overseas Thrust. The work in Japan was supported by the Japan Society for the Promotion of Science (JSPS contract Nº PE10027). J.C. Gonzalez thanks to CSIC for his JAE-Doc contract (2009-2012) at the ICMSE-CSIC-US (Spain), and to the Consejería de Economía, Innovación y Ciencia of the Junta de Andalucía (Project FQM-6900) for financial support. The authors are indebted to Dr. D. W. Lee from the Nanyang Technological University (Singapore) for his helpful discussions.