摘要
Metal-organic chemical vapor deposition was applied to fabricate YBa2Cu3OT-a （YBCO） films on singlecrystal LaA103 （001） substrates for its high deposition rate, easy adjustment on film composition, and low requirement on vacuum apparatus. The effects of Cu（tmhd）2 concentra- tion in the precursor on the properties of YBCO films were systematically investigated. X-ray diffraction （XRD） reveals that the mole ratio of Cu/Ba in the precursor from 0.77 to 0.97 is helpful to improve the crystallization and out-of-plane orientation of YBCO films; however, it hardly affects the inplane texture. Scanning electron microscope （SEM） shows the dense, crack-free but rough surface, on which there are Cu-O and Ba-Cu-O outgrowths identified by energy-dispersive spectrometer （EDS）. As the mole ratio of Cu/Ba increasing, the average size of Ba-Cu-O precipitates keeps increasing and the film composition becomes inhomoge- neous at the mole ratio of Cu/Ba of 0.97. The 250 nm thick YBCO film prepared at the mole ratio of Cu/Ba of 0.91 shows the critical current density （Jc） of 4.0 MA.cm-2 （77 K, 0 T）.
Metal-organic chemical vapor deposition was applied to fabricate YBa2Cu3OT-a （YBCO） films on singlecrystal LaA103 （001） substrates for its high deposition rate, easy adjustment on film composition, and low requirement on vacuum apparatus. The effects of Cu（tmhd）2 concentra- tion in the precursor on the properties of YBCO films were systematically investigated. X-ray diffraction （XRD） reveals that the mole ratio of Cu/Ba in the precursor from 0.77 to 0.97 is helpful to improve the crystallization and out-of-plane orientation of YBCO films; however, it hardly affects the inplane texture. Scanning electron microscope （SEM） shows the dense, crack-free but rough surface, on which there are Cu-O and Ba-Cu-O outgrowths identified by energy-dispersive spectrometer （EDS）. As the mole ratio of Cu/Ba increasing, the average size of Ba-Cu-O precipitates keeps increasing and the film composition becomes inhomoge- neous at the mole ratio of Cu/Ba of 0.97. The 250 nm thick YBCO film prepared at the mole ratio of Cu/Ba of 0.91 shows the critical current density （Jc） of 4.0 MA.cm-2 （77 K, 0 T）.
基金
financially supported by the Sichuan Youth Science and Technology Innovation Research Team(No.2011JTD0006)
the Fundamental Research Funds for the Central Universities(Nos.ZYGX2012J039 and ZYGX2011Z002)
