采用 LBL(layer- by- layer)法制备了 Cu2 Sn S3 薄膜。即首先采用电化学方法在 Sn O2 衬底上制备 Sn S薄膜 ,然后又在其上用化学沉积法制备 Cu S薄膜 ,最后进行退火处理得到厚度约为960 nm的 Cu2 Sn S3 薄膜。探讨了薄膜的制备机理、...采用 LBL(layer- by- layer)法制备了 Cu2 Sn S3 薄膜。即首先采用电化学方法在 Sn O2 衬底上制备 Sn S薄膜 ,然后又在其上用化学沉积法制备 Cu S薄膜 ,最后进行退火处理得到厚度约为960 nm的 Cu2 Sn S3 薄膜。探讨了薄膜的制备机理、生长速度、结构和光学特性。制备的薄膜为多晶(Cu2 Sn S3 ) 72 z(三斜或假单斜晶系 )结构 ,其直接光学带隙约为 1 .0 5 e V。展开更多
In this study, we have explored the ways to fabricate and optimize high-quality ultrathin YBa2 Cu3 O7-δ(YBCO) films grown on single-crystal(001) SrTiO3 substrates. Nearly atomic-flat YBCO films are obtained by pulsed...In this study, we have explored the ways to fabricate and optimize high-quality ultrathin YBa2 Cu3 O7-δ(YBCO) films grown on single-crystal(001) SrTiO3 substrates. Nearly atomic-flat YBCO films are obtained by pulsed laser deposition.Our result shows that the termination of SrTiO3 has only a negligible effect on the properties of YBCO. In contrast, we found that capping a non-superconducting oxide layer can generally enhance the superconductivity of YBCO. PrBa2 Cu3 O7,La2 CuO4, LaMnO3, SrTiO3, and LaAlO3 have been examined as capping layers, and the minimum thickness of superconducting YBCO with capping is ~ 2 unit cells–3 unit cells. This result might be useful in constructing good-performance YBCO-based field effect devices.展开更多
Excellent epitaxial growth of supercon-ducting YBaCuOthin films have beenrealized on(100)SrTiOand(100)ZrOsubstrates by a planar rf or DC-magnetronsputtering apparatus with UHV system.Thequality of growth and the epita...Excellent epitaxial growth of supercon-ducting YBaCuOthin films have beenrealized on(100)SrTiOand(100)ZrOsubstrates by a planar rf or DC-magnetronsputtering apparatus with UHV system.Thequality of growth and the epitaxial orientationof the film strongly depended on substratetemperature,the substrate orientation and ox-ygen partial pressure.The films exhibitedsuperconducting onset at 92K and zero resist-ance at 90K with critical current density of展开更多
The bonding and electronic structure of Cu/(0001)Al2O3 and Cu/(1120)Al2O3 interfaces has been studied experimentally using spatially-resolved transmission electron energy loss spectroscopy. The specimen were prepared ...The bonding and electronic structure of Cu/(0001)Al2O3 and Cu/(1120)Al2O3 interfaces has been studied experimentally using spatially-resolved transmission electron energy loss spectroscopy. The specimen were prepared by depositing Cu on single-crystal α-AI2O3 substrates, which have been Ar+-ion sputter-cleaned prior to the growth of Cu. For both orientations of the α-Al2O3 substrate, atomically abrupt interfaces formed as determined by high-resolution transmission electron microscopy. The investigations of the interfacial Cu-L2,3, Al-L2,3 and 0-K energy loss near-edge structures, which are proportional to the site- and angular-momentum-projected unoccupied density of states above the Fermi level, indicate the existence of metallic Cu-AI bonds at the Cu/AI2O3 interface independent of the substrate orientation.展开更多
We report the thickness dependence of critical current density （Jc） in YBa2Cu3O7-x （YBCO） films with BaZrO3 （BZO） and Y2O3 additions grown on single crystal LaAlO3 substrates by metalorganic deposition using tri...We report the thickness dependence of critical current density （Jc） in YBa2Cu3O7-x （YBCO） films with BaZrO3 （BZO） and Y2O3 additions grown on single crystal LaAlO3 substrates by metalorganic deposition using trifluoroacetates （TFA-MOD）. Comparing with pttre YBCO films, the Jc of BZO/Y2O3-doped YBCO films was significantly enhanced. It was also found that with the increase of the thickness of YBCO film from 0.25 μm to 1.5 μm, the Ic of BZO/Y2O3-doped YBCO film increased from 130 A/cm to 250 A/cm and yet Jc of YBCO film decreased from 6.5 MA/cm2 to 2.5 M A/cm2. The thick BZO/Y2O3-doped MOD-YBCO film showed lower Jc, which is mainly attributed to the formation of a-axis grains and pores.展开更多
The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain ...The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain 0 and the irreversible strain εirr. By introducing the applied strain, a modified grain boundaries （GBs） in the REBCO film is developed. lattice model combining the strain and misorientation of A good agreement of the calculation on the lattice model with the experimental data shows that the lattice model is able to well describe the reversible effect of axial strain on the critical current of the REBCO film, and provides a good understanding of the mechanism of the reversible effect of the strain. Moreover, the effects of the crystallographic texture of the REBCO film and the residual strain εr on the variation of the critical current with the applied strain are extensively investigated. Furthermore by using the developed lattice model, the irreversible strain εirr of the REBCO film can be theoretically determined by comparing the calculation of the critical current-strain curve with the experimental data.展开更多
文摘采用 LBL(layer- by- layer)法制备了 Cu2 Sn S3 薄膜。即首先采用电化学方法在 Sn O2 衬底上制备 Sn S薄膜 ,然后又在其上用化学沉积法制备 Cu S薄膜 ,最后进行退火处理得到厚度约为960 nm的 Cu2 Sn S3 薄膜。探讨了薄膜的制备机理、生长速度、结构和光学特性。制备的薄膜为多晶(Cu2 Sn S3 ) 72 z(三斜或假单斜晶系 )结构 ,其直接光学带隙约为 1 .0 5 e V。
基金Project supported by the National Key Research and Development Program of the Ministry of Science and Technology of China(Grants Nos.2017YFA0303002and 2016YFA0300204)the Fundamental Research Funds for the Central Universities,China
文摘In this study, we have explored the ways to fabricate and optimize high-quality ultrathin YBa2 Cu3 O7-δ(YBCO) films grown on single-crystal(001) SrTiO3 substrates. Nearly atomic-flat YBCO films are obtained by pulsed laser deposition.Our result shows that the termination of SrTiO3 has only a negligible effect on the properties of YBCO. In contrast, we found that capping a non-superconducting oxide layer can generally enhance the superconductivity of YBCO. PrBa2 Cu3 O7,La2 CuO4, LaMnO3, SrTiO3, and LaAlO3 have been examined as capping layers, and the minimum thickness of superconducting YBCO with capping is ~ 2 unit cells–3 unit cells. This result might be useful in constructing good-performance YBCO-based field effect devices.
文摘Excellent epitaxial growth of supercon-ducting YBaCuOthin films have beenrealized on(100)SrTiOand(100)ZrOsubstrates by a planar rf or DC-magnetronsputtering apparatus with UHV system.Thequality of growth and the epitaxial orientationof the film strongly depended on substratetemperature,the substrate orientation and ox-ygen partial pressure.The films exhibitedsuperconducting onset at 92K and zero resist-ance at 90K with critical current density of
文摘The bonding and electronic structure of Cu/(0001)Al2O3 and Cu/(1120)Al2O3 interfaces has been studied experimentally using spatially-resolved transmission electron energy loss spectroscopy. The specimen were prepared by depositing Cu on single-crystal α-AI2O3 substrates, which have been Ar+-ion sputter-cleaned prior to the growth of Cu. For both orientations of the α-Al2O3 substrate, atomically abrupt interfaces formed as determined by high-resolution transmission electron microscopy. The investigations of the interfacial Cu-L2,3, Al-L2,3 and 0-K energy loss near-edge structures, which are proportional to the site- and angular-momentum-projected unoccupied density of states above the Fermi level, indicate the existence of metallic Cu-AI bonds at the Cu/AI2O3 interface independent of the substrate orientation.
基金supported by the National Natural Science Foundation of China(Grant No.51272250)the National Basic Research Program of China(Grant No.2011CBA00105)+1 种基金the National High Technology Research and Development Program of China(Grant No.2014AA032702)the Beijing Natural Science Foundation,China(Grant No.2152035)
文摘We report the thickness dependence of critical current density （Jc） in YBa2Cu3O7-x （YBCO） films with BaZrO3 （BZO） and Y2O3 additions grown on single crystal LaAlO3 substrates by metalorganic deposition using trifluoroacetates （TFA-MOD）. Comparing with pttre YBCO films, the Jc of BZO/Y2O3-doped YBCO films was significantly enhanced. It was also found that with the increase of the thickness of YBCO film from 0.25 μm to 1.5 μm, the Ic of BZO/Y2O3-doped YBCO film increased from 130 A/cm to 250 A/cm and yet Jc of YBCO film decreased from 6.5 MA/cm2 to 2.5 M A/cm2. The thick BZO/Y2O3-doped MOD-YBCO film showed lower Jc, which is mainly attributed to the formation of a-axis grains and pores.
基金Supported by the National Natural Science Foundation of China under Grant No 11372096the Research Fund for the Doctoral Program of Higher Education of China
文摘The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain 0 and the irreversible strain εirr. By introducing the applied strain, a modified grain boundaries （GBs） in the REBCO film is developed. lattice model combining the strain and misorientation of A good agreement of the calculation on the lattice model with the experimental data shows that the lattice model is able to well describe the reversible effect of axial strain on the critical current of the REBCO film, and provides a good understanding of the mechanism of the reversible effect of the strain. Moreover, the effects of the crystallographic texture of the REBCO film and the residual strain εr on the variation of the critical current with the applied strain are extensively investigated. Furthermore by using the developed lattice model, the irreversible strain εirr of the REBCO film can be theoretically determined by comparing the calculation of the critical current-strain curve with the experimental data.
基金supported by the National Natural Science Foundation of China(Nos.52105369,61974070)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.20KJB460008)+1 种基金Natural Science Foundation of Jiangsu Province,China(No.BK20200746)NUPTSF(No.NY220077).
