This paper systematically investigates the intermediate phases of YBa2Cu3O7-x （YBCO） film prepared by metalorganic deposition method using trifluoroacetates （TFA-MOD）. According to x-ray diffraction and Raman anal...This paper systematically investigates the intermediate phases of YBa2Cu3O7-x （YBCO） film prepared by metalorganic deposition method using trifluoroacetates （TFA-MOD）. According to x-ray diffraction and Raman analyses, the precursor film decomposed in a mixture of BaF2, Y203 and CuO after the pyrolysis process. Then these inter- mediate phases converted into tetragonal YBa2Cu3O6.5 at about 725 ℃. The influence of water vapour pressure on the YBa2Cu3O7-x film growth on LaAlO3 single-crystal substrates was also studied. The films prepared at low water vapour pressures （40-140 hPa） showed poor electrical performance due to the a-axis grain structure and impurity phases. However, the films prepared at 190hPa exhibited the highest critical temperature of 90 K and the highest Jc of 3.8 MA/cm2, which was attributed to the formation of a purer YBCO phase and stronger biaxial texture.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 50672011)the Hi-Tech Research and Development Program of China (Grant No 2007AA03Z216)
文摘This paper systematically investigates the intermediate phases of YBa2Cu3O7-x （YBCO） film prepared by metalorganic deposition method using trifluoroacetates （TFA-MOD）. According to x-ray diffraction and Raman analyses, the precursor film decomposed in a mixture of BaF2, Y203 and CuO after the pyrolysis process. Then these inter- mediate phases converted into tetragonal YBa2Cu3O6.5 at about 725 ℃. The influence of water vapour pressure on the YBa2Cu3O7-x film growth on LaAlO3 single-crystal substrates was also studied. The films prepared at low water vapour pressures （40-140 hPa） showed poor electrical performance due to the a-axis grain structure and impurity phases. However, the films prepared at 190hPa exhibited the highest critical temperature of 90 K and the highest Jc of 3.8 MA/cm2, which was attributed to the formation of a purer YBCO phase and stronger biaxial texture.
