In research of YBCO coated conductors, the development of a oxide template for epitaxial growth of YBCO is very important. Matsumoto et al have demonstrated the potential of the surface oxidation epitaxial (SOE) route...In research of YBCO coated conductors, the development of a oxide template for epitaxial growth of YBCO is very important. Matsumoto et al have demonstrated the potential of the surface oxidation epitaxial (SOE) route for formation a cube textured NiO layer on nickel tapes. The epitaxial NiO functions as a buffer layer of chemical reaction between YBCO and nickel, and as a template for the epitaxial growth of YBCO. However, the surface quality of NiO is difficult to control and defects such as crack, spall and deep grooves exist in SOE NiO layer. A new approach combining sputtering and SOE method to obtain crack-free and cube textured NiO layer were reported. Ni tapes prepared by the combination of rolling and recrystallization were used for this work. A coating of Ni was first deposited on the tapes via magnetron sputtering. Then on the coating tapes, continuous and textured NiO layer were achieved by SOE technology.展开更多
MgO thin films with different textures are fabricated by the ion beam assisted （IBAD） method on the Y2O3/Al2O3 buffered C276 tape. Then a CaO2 layer is directly grown on the IBAD-MgO film by the pulsed laser deposit...MgO thin films with different textures are fabricated by the ion beam assisted （IBAD） method on the Y2O3/Al2O3 buffered C276 tape. Then a CaO2 layer is directly grown on the IBAD-MgO film by the pulsed laser deposition （PLD） method. Effects of lBAD-MgO texture, substrata 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 CaO2 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 substrata 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 △φ = 2.9° and a smooth surface with an rms surface roughness of less than 2nm. The critical current density Jc of a 0.4μm-thick YBCO film deposited on the CeO2 layer is 6.25 × 106 A/cm2 at 77K and a self-field.展开更多
CeO2/YSZ/CeO2 buffer layers were prepared on biaxial textured Ni-5at.%W substrate by direct-current magnetron reactive sputtering with the optimum process. YBCO thin films were deposited on CeO2/YSZ/CeO2 buffered Ni-5...CeO2/YSZ/CeO2 buffer layers were prepared on biaxial textured Ni-5at.%W substrate by direct-current magnetron reactive sputtering with the optimum process. YBCO thin films were deposited on CeO2/YSZ/CeO2 buffered Ni-5at.%W substrate at temperature ranging from 500℃ to 700℃ by diode de sputtering. By optimizing substrate temperature, pure c-axis oriented YBCO films were obtained. The mierostruetures of CeO2/YSZ/CeO2 buffer layers were characterized by X-ray diffraction. A smooth, dense and crack-free surface morphology was observed with scanning electron microscopy. The critical current density Jc about 0.75 MA/cm2 at 77 K was obtained.展开更多
YBCO high temperature coated conductors are the most promising candidate for large scale superconducting transmission cables and fault current limiters. A modified TFA-MOD method was applied to prepare YBCO layer on R...YBCO high temperature coated conductors are the most promising candidate for large scale superconducting transmission cables and fault current limiters. A modified TFA-MOD method was applied to prepare YBCO layer on Rolling Assisted Biaxially Textured Substrate (RABiTS) with textured Y 2 O 3 /YSZ/CeO 2 buffer layers, resulting in reduced time and cost of fabrication. By using Cu naphthenate instead of Cu(TFA) 2 , the pyrolysis time of the YBCO precursors was reduced significantly. YBCO films with thickness of 2 μm were fabricated with multiple-coating and annealed at high temperature for 2 h. X-ray diffraction analysis revealed that the films were c-axis oriented. The preliminary results of YBCO films yielded 0.2 MA/cm 2 at 77 K and self field. It is believed current carrying ability of YBCO films could be further improved by reducing the reaction rate at the interface between the buffer layer and superconducting layer.展开更多
Superconducting YBa2Cu3O7-x films were grown on the CeO2/YSZ/Y2O3 buffered rolling assisted biaxial textured Ni-5at%W substrate by MOCVD method. Self-made Y(DPM)3, Ba(DPM)2, and Cu(DPM)2 were used as the precursors. D...Superconducting YBa2Cu3O7-x films were grown on the CeO2/YSZ/Y2O3 buffered rolling assisted biaxial textured Ni-5at%W substrate by MOCVD method. Self-made Y(DPM)3, Ba(DPM)2, and Cu(DPM)2 were used as the precursors. Different ratios of the precursors were applied to optimize the hetero-epitaxial structure and property of YBCO films. X-ray diffraction revealed that YBCO films had excellent in plane texture with full width at half maximum (FWHM) value of (103)=5.6°-6.5° and out-of-plane texture with FWHM of (005)=3.1°-3.7°. The superconductivity of YBCO films was measured. The relationship between the ratios of the precursors and the property of the films were discussed in detail.展开更多
The advance in first generation Bi-2223 HTS wire has enabled the demonstration of superconducting power cables, magnetic energy-storage devices, transformers,fault current limiters and motors. However, the low irrever...The advance in first generation Bi-2223 HTS wire has enabled the demonstration of superconducting power cables, magnetic energy-storage devices, transformers,fault current limiters and motors. However, the low irreversibility field (H^*) prevents application of Bi-2223 at 77 Kin any significant field. Worldwide activities are therefore,focused on developing a second-generation HTS technology based on YBCO, for which H^* (77K)-7 T. In this paper, we discuss the status and commercial prospects of second generation HTS wire technologies. In addition, we review the recent results and discuss the prospects of future applications.展开更多
A full solution method has been developed as a low cost process of YBa2Cu3OT-x （YBCO） coated conductor fabrication. In this study, highly biaxially textured SrTiO3 （STO） buffer layers were fabricated on LaAlO3 （...A full solution method has been developed as a low cost process of YBa2Cu3OT-x （YBCO） coated conductor fabrication. In this study, highly biaxially textured SrTiO3 （STO） buffer layers were fabricated on LaAlO3 （LAO） single crystal substrates by sol-gel method using metal alkoxides as the staring precursor materials. High quality YBCO superconducting film was then fabricated on STO-buffered LAO substrate by trifluoroacetic metalorganic deposition （TFA-MOD） method. For the YBCO superconducting film, only （001） diffraction peaks can be detected by XRD （X-ray diffraction） analysis with no other phases detectable. Especially, Inplane texture of YBCO film is improved compared to that of STO buffer layer from phi scans analysis, which indicates the self-epitaxy phenomenon explained by considering interracial energy. STO and YBCO films both show c-axis oriented grains growth and have uniform surface microstructure. A critical transition temperature, TC （R=0） of 89.5 K and a critical current density of 2 mA/cm2 （77 K, self-field） were obtained for a 0.2μm thick YBCO film on STO-buffered LAO substrate. No reaction between YBCO and STO was detected by XRD analysis. This full solution process may provide a promising low cost fabrication route for YBCO coated conductors on metal tape.展开更多
文摘In research of YBCO coated conductors, the development of a oxide template for epitaxial growth of YBCO is very important. Matsumoto et al have demonstrated the potential of the surface oxidation epitaxial (SOE) route for formation a cube textured NiO layer on nickel tapes. The epitaxial NiO functions as a buffer layer of chemical reaction between YBCO and nickel, and as a template for the epitaxial growth of YBCO. However, the surface quality of NiO is difficult to control and defects such as crack, spall and deep grooves exist in SOE NiO layer. A new approach combining sputtering and SOE method to obtain crack-free and cube textured NiO layer were reported. Ni tapes prepared by the combination of rolling and recrystallization were used for this work. A coating of Ni was first deposited on the tapes via magnetron sputtering. Then on the coating tapes, continuous and textured NiO layer were achieved by SOE technology.
基金Supported by the ITER Project of the Ministry of Science and Technology of China under Grant No 2011GB113004the Shanghai Commission of Science and Technology under Grant Nos 09DZ1206000 and 11DZ1100402the Youth Fund of Natural Science Foundation of China under Grant No 11204174
文摘MgO thin films with different textures are fabricated by the ion beam assisted （IBAD） method on the Y2O3/Al2O3 buffered C276 tape. Then a CaO2 layer is directly grown on the IBAD-MgO film by the pulsed laser deposition （PLD） method. Effects of lBAD-MgO texture, substrata 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 CaO2 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 substrata 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 △φ = 2.9° and a smooth surface with an rms surface roughness of less than 2nm. The critical current density Jc of a 0.4μm-thick YBCO film deposited on the CeO2 layer is 6.25 × 106 A/cm2 at 77K and a self-field.
文摘CeO2/YSZ/CeO2 buffer layers were prepared on biaxial textured Ni-5at.%W substrate by direct-current magnetron reactive sputtering with the optimum process. YBCO thin films were deposited on CeO2/YSZ/CeO2 buffered Ni-5at.%W substrate at temperature ranging from 500℃ to 700℃ by diode de sputtering. By optimizing substrate temperature, pure c-axis oriented YBCO films were obtained. The mierostruetures of CeO2/YSZ/CeO2 buffer layers were characterized by X-ray diffraction. A smooth, dense and crack-free surface morphology was observed with scanning electron microscopy. The critical current density Jc about 0.75 MA/cm2 at 77 K was obtained.
基金National Science Foundation of China (51002024)"863" High-Tech Project (2007AA03Z201)
文摘YBCO high temperature coated conductors are the most promising candidate for large scale superconducting transmission cables and fault current limiters. A modified TFA-MOD method was applied to prepare YBCO layer on Rolling Assisted Biaxially Textured Substrate (RABiTS) with textured Y 2 O 3 /YSZ/CeO 2 buffer layers, resulting in reduced time and cost of fabrication. By using Cu naphthenate instead of Cu(TFA) 2 , the pyrolysis time of the YBCO precursors was reduced significantly. YBCO films with thickness of 2 μm were fabricated with multiple-coating and annealed at high temperature for 2 h. X-ray diffraction analysis revealed that the films were c-axis oriented. The preliminary results of YBCO films yielded 0.2 MA/cm 2 at 77 K and self field. It is believed current carrying ability of YBCO films could be further improved by reducing the reaction rate at the interface between the buffer layer and superconducting layer.
文摘Superconducting YBa2Cu3O7-x films were grown on the CeO2/YSZ/Y2O3 buffered rolling assisted biaxial textured Ni-5at%W substrate by MOCVD method. Self-made Y(DPM)3, Ba(DPM)2, and Cu(DPM)2 were used as the precursors. Different ratios of the precursors were applied to optimize the hetero-epitaxial structure and property of YBCO films. X-ray diffraction revealed that YBCO films had excellent in plane texture with full width at half maximum (FWHM) value of (103)=5.6°-6.5° and out-of-plane texture with FWHM of (005)=3.1°-3.7°. The superconductivity of YBCO films was measured. The relationship between the ratios of the precursors and the property of the films were discussed in detail.
文摘The advance in first generation Bi-2223 HTS wire has enabled the demonstration of superconducting power cables, magnetic energy-storage devices, transformers,fault current limiters and motors. However, the low irreversibility field (H^*) prevents application of Bi-2223 at 77 Kin any significant field. Worldwide activities are therefore,focused on developing a second-generation HTS technology based on YBCO, for which H^* (77K)-7 T. In this paper, we discuss the status and commercial prospects of second generation HTS wire technologies. In addition, we review the recent results and discuss the prospects of future applications.
基金supported by the National Natural Science Foundation of China under contract No.50606027the National High Technology Research and Development Program ("863 program") under contract No.2002AA306211the International Collaboration Project under contract No.2004AA32H020.
文摘A full solution method has been developed as a low cost process of YBa2Cu3OT-x （YBCO） coated conductor fabrication. In this study, highly biaxially textured SrTiO3 （STO） buffer layers were fabricated on LaAlO3 （LAO） single crystal substrates by sol-gel method using metal alkoxides as the staring precursor materials. High quality YBCO superconducting film was then fabricated on STO-buffered LAO substrate by trifluoroacetic metalorganic deposition （TFA-MOD） method. For the YBCO superconducting film, only （001） diffraction peaks can be detected by XRD （X-ray diffraction） analysis with no other phases detectable. Especially, Inplane texture of YBCO film is improved compared to that of STO buffer layer from phi scans analysis, which indicates the self-epitaxy phenomenon explained by considering interracial energy. STO and YBCO films both show c-axis oriented grains growth and have uniform surface microstructure. A critical transition temperature, TC （R=0） of 89.5 K and a critical current density of 2 mA/cm2 （77 K, self-field） were obtained for a 0.2μm thick YBCO film on STO-buffered LAO substrate. No reaction between YBCO and STO was detected by XRD analysis. This full solution process may provide a promising low cost fabrication route for YBCO coated conductors on metal tape.
