共查询到20条相似文献,搜索用时 15 毫秒
1.
R. Fuger M. Eisterer S.S. Oh H.W. Weber 《Physica C: Superconductivity and its Applications》2010,470(5-6):323-325
In addition to the well investigated YBa2Cu3O7?δ (Y-123, YBCO) compound, many other rare earth-123 compounds are candidate materials for the production of coated conductors. Sm-123 seems to be an excellent alternative because of its higher transition temperature (Tc) and higher critical current densities (Jc) in external magnetic fields. Because of the fast decrease of Jc in YBCO at elevated temperatures, especially around the boiling point of liquid nitrogen, the slightly higher Tc can be an important advantage. Recently, significant progress has been made in the production of long length Sm-123 based coated conductors. We report here on transport measurements on these conductors in the liquid nitrogen temperature range. The critical current densities were determined as a function of the applied field and the crystallographic orientation under maximum Lorentz force configuration. A shift of the c-axis (~7°) from the tape normal was found. The conductor properties were compared to those of commercially available YBCO coated conductors. The critical current densities as well as the irreversibility fields are higher in the SmBCO tapes, thus demonstrating the superior properties of the Sm-123 compound. 相似文献
2.
Biaxially textured YBa2Cu3O7−x (YBCO) films were grown on inclined-substrate-deposited (ISD) MgO-textured metal substrates by pulsed laser deposition. CeO2 was deposited as a buffer layer prior to YBCO growth. CeO2 layers of different thickness were prepared to evaluate the thickness dependence of the YBCO films. The biaxial alignment features of the films were examined by X-ray diffraction 2θ-scans, pole-figure, ?-scans and rocking curves of Ω angles. The significant influence of the CeO2 thickness on the structure and properties of the YBCO films were demonstrated and the optimal thickness was found to be about 10 nm. High values of Tc = 91 K and Jc = 5.5 × 105 A/cm2 were obtained on YBCO films with optimal CeO2 thickness at 77 K in zero field. The possible mechanisms responsible for the dependence of the structure and the properties of the YBCO films on the thickness of the CeO2 buffer layers are discussed. 相似文献
3.
The experiments on explosion of cylindrical conductors aimed at comparison of plasma formation during skin explosion of homogeneous and double-layer conductors with an external layer with a lower conductivity are carried out on a high-current MIG generator (current amplitude up to 2.5 MA and current rise time 100 ns). The generator is loaded with cylindrical copper conductors with a diameter of 3 mm on the cathode part of which a titanium layer of thickness 20, 50, and 80 μm is deposited in vacuum. This type of loading makes it possible to compare the behaviors of the homogeneous and double-layer conductors in identical conditions. It is shown that using the double-layer structure of the conductor with an external layer of thickness 20–80 μm with a lower conductivity, which is obtained by vacuum arc deposition, higher values of magnetic induction (as compared to homogeneous conductor) can be attained on its surface prior to plasma formation and spread. 相似文献
4.
H. Huang S.X. Lu W.K. Zhang Y.P. Gan C.T. Wang L. Yu X.Y. Tao 《Journal of Physics and Chemistry of Solids》2009,70(3-4):745-749
N-doped TiO2 film was synthesized on indium–tin oxide (ITO) conducting glass substrate by the hydrolysis method and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Then high porous NiO was deposited onto the TiO2?xNx layer by chemical bath deposition (CBD) to prepare a double-layer TiO2?xNx/NiO electrode. The photoelectrochromic properties of the TiO2?xNx/NiO electrode were discussed through the results of UV–vis transmittance spectra, cyclic voltammogram and photocurrent transient measurements. It was found that the TiO2?xNx/NiO electrode was sensitive to light and exhibited a noticeable photoelectrochromism. The NiO film changed its color from colorless to brown, and the transmittance varied from 86.8% to 14.5% at 500 nm after 1 h irradiation. 相似文献
5.
The optical properties of gold layer deposited on antireflection subwavelength-structured surface are first exposed. The experimental results of the reflectances and transmittances for several different thicknesses of gold-deposited layers on the subwavelength structures are carried out. The nanostructured surface with spatial period and a diameter of about 230 nm and height of about 150 nm on polyethylene terphthalate (PET) film is fabricated by micro-replication process of UV imprinting. Comparing these with the bare gold-deposited layer and bare nanostructure, the results show that the optical films with the suitable gold layer deposited on antireflection subwavelength-structured surface has high transmittance and low glare in the visible spectral range and high reflectance in the infrared range. That is to say, when the antireflection subwavelength-structured surface is coated with a gold layer of several tens of nm thickness, it will have some unique optical characters. 相似文献
6.
电化学沉积法制备高温超导YBa2Cu3O7-δ涂层导体缓冲层具有工艺简单、设备要求低、易于连续化批量制备等优点。采用电化学沉积法,在双轴织构的Ni-5at.%W(Ni-5W)金属基带上成功制备出了具有良好c轴取向的CeO2缓冲层薄膜。利用X射线衍射、极图、扫描电子显微镜和原子力显微镜等对上述氧化物薄膜的织构、表面形貌等进行表征。重点研究了薄膜厚度、退火温度、退火时间等工艺对薄膜外延生长及其表面形貌的影响,结果表明:电化学沉积方法制备的CeO2缓冲层具有很好的双轴织构、表面平整、均一,粗糙度低,表现出良好的缓冲层性质。结合金属有机化学溶液超导层的制备技术,本工作展示了一条全化学法制备第二代高温超导带材的技术路线,具有很好的应用前景。 相似文献
7.
N. V. Vostokov S. V. Gaponov B. A. Gribkov Yu. N. Drozdov D. V. Masterov V. L. Mironov Yu. N. Nozdrin E. E. Pestov 《Physics of the Solid State》2003,45(11):2025-2030
The surface morphology and superconducting properties of YBaCuO epitaxial films prepared through magnetron sputtering from targets of different cation composition were systematically studied. It was shown that small changes in the growth conditions and relatively small variations in the cation composition of the condensate noticeably affect the surface morphology of the films and their structural and superconducting properties, thus offering an efficient way of controlling the YBCO film parameters. It was found that the 90° off-axis configuration of the magnetron sputtering system permits realization of growth conditions in which the grown films do not contain CuO precipitates and exhibit good superconducting properties (Tc≥88 K, jc(77 K)≥4×106 A/cm2). 相似文献
8.
PAN Min HUANG Zheng MA HuanFeng QIANG WeiRong WEI LianFu WANG Long & ZHAO Yong Key Laboratory of Magnetic Levitation Technologies Maglev Trains Superconductivity R&D Center Southwest Jiaotong University Chengdu China School of Physical Science Technology Superconductivity Research Group School of Materials Science Engineering University of New South Wale Sydney ... 《中国科学G辑(英文版)》2009,(7)
The lattice parameters, band structure, density of state and elastic constant of RE-doped CeO2 (RE=Sm, Gd, Dy), the buffer material for coated HTS conductors, are calculated using the plane-wave method with pseudopotentials based on the density functional theory (DFT) of first-principle. The rule and mechanism of the effect of rare earth impurity on the critical thickness of the CeO2 buffer layer are investigated. It is found that, in the range of the calculation, the changes of the lattice volume V and ela... 相似文献
9.
The effect of poly-Si thickness on silicidation of Ni film was investigated by using X-ray diffraction, auger electron spectroscopy, cross-sectional scanning transmission electron microscopy, resistivity, I–V, and C–V measurements. The poly-Si films with various thickness of 30–200 nm were deposited by LPCVD on thermally grown 50 nm thick SiO2, followed by deposition of Ni film right after removing the native oxide. The Ni film was prepared by using atomic layer deposition with a N2-hydroxyhexafluoroisopropyl-N1 (Bis-Ni) precursor. Rapid thermal process was then applied for a formation of fully silicide (FUSI) gate at temperature of 500 °C in N2 ambient during 30 s. The resultant phase of Ni-silicide was strongly dependent on the thickness of poly-Si layer, continuously changing its phase from Ni-rich (Ni3Si2) to Si-rich (NiSi2) with increasing the thickness of the poly-Si layer, which is believed to be responsible for the observed flat band voltage shift, ΔVFB, in C–V curves. 相似文献
10.
Zhihao Yue Honglie Shen Ye Jiang Wei Wang Jiale Jin 《Applied Physics A: Materials Science & Processing》2014,114(3):813-817
In this paper, nickel nanoparticles (Ni NPs) were deposited on planar silicon and pyramidal silicon wafers by the magnetron sputtering method, and then these Ni NP-covered samples were etched in a hydrofluoric acid, hydrogen peroxide, and deionized water mixed solution at room temperature to fabricate a low reflective silicon surface. An alumina (Al2O3) film was then deposited on the surface of the as-etched pyramidal sample by atomic layer deposition to further reduce the reflectance. The morphologies and compositions of these samples were studied by using a field emission scanning electron microscope attached to an energy-dispersive X-ray spectrometer. The surface reflectance measurements were carried out with a UV-Vis-NIR spectrophotometer in a wavelength range of 200–1100 nm. The SEM images show that the as-etched planar and pyramidal silicon samples were covered with many rhombic nanostructures and that some nanostructures on the planar silicon surface were ready to exhibit a flower-like burst. The reflectances of the as-etched planar and pyramidal silicon samples were 5.22 % and 3.21 % in the wavelength range of 400–800 nm, respectively. After being coated with a 75-nm-thick Al2O3 film, the etched pyramidal silicon sample showed an even lower reflectance of 2.37 % from 400 nm to 800 nm. 相似文献
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热退火是多孔低介电常数薄膜制备过程中的重要一环, 对薄膜结构及性能具有重要影响. 本文以四乙氧基硅烷和双戊烯为前驱体, 采用等离子体增强化学气相沉积方法制备了SiCOH薄膜, 对其进行了氮气氛围下的热退火处理, 分析了热退火对薄膜结构与性能的影响, 探究了退火过程中薄膜结构变化的可能的反应机理. 傅里叶变换红外光谱和固体核磁共振谱结果表明, 沉积薄膜是一种有机无机杂化薄膜. 退火过程中, 薄膜中的-CH2, -CH3等有机组分被分解除去, 形成了以稳定的Si-O-Si等无机组分为骨架的多孔结构, 并通过氮气吸附/脱附等温线测试得到了验证. 在此期间, 薄膜骨架微结构亦发生一系列调整, C=C, Si-C含量增加, Si、O、C等元素间发生进一步键合. C=C 含量的提高, 使得薄膜的消光系数和漏电流密度增大. 实验证明, 退火后薄膜具有低折射率、低介电常数特性, 是一类具有优异的介电性能和力学性能的材料, 作为芯片后端互连层间介质具有极大的应用潜力. 相似文献
13.
The effect of the laser sputtering parameters on the crystal properties of CeO2 buffer layers grown on a ( $1\underset{\raise0.3em\hbox{$1\underset{\raise0.3em\hbox{ ) sapphire substrate and on the properties of superconducting YBa2Cu3Ox thin films are investigated. It is shown that (100) and (111) CeO2 growth is observed, depending on the sputtering conditions. A buffer layer with the desired unidirectional orientation can be obtained by varying the heater temperature, the pressure in the chamber, and the energy density of the laser beam at the target. 相似文献
14.
Polybithiophene (PBTh) film was used as a hole-transport layer in an electroluminescent (EL) device. The PBTh was electropolymerized on indium tin oxide (ITO)-coated glass acting as a working electrode. From the change of full width at half maximum (FWHM) of the EL spectrum with the thickness of the PBTh film, it could be deduced that the PBTh film efficiently blocks the injection of electrons into the ITO electrode. The thickness of the hole-transport layer used in the EL device has a significant influence on the EL intensity and efficiency. Experimental data showed that there is an optimal thickness of the electrodeposited PBTh-hole-transport layer for high-efficiency EL devices. 相似文献
15.
Effect of oxygen partial pressure on the structural and optical properties of ZnO film deposited by reactive sputtering 总被引:1,自引:0,他引:1
J.P. Zhang G. He L.Q. Zhu M. Liu S.S. Pan L.D. Zhang 《Applied Surface Science》2007,253(24):9414-9421
Effects of variation of the oxygen partial pressure on the structural and optical properties of zinc oxide (ZnO) thin films prepared by reactive radio-frequency sputtering were investigated. Measurements by X-ray diffraction (XRD) and atomic force microscopy (AFM) indicated that the crystallinity and the surface morphology were sensitive to the oxygen partial pressure. The interfacial and optical properties of the targeted films were investigated by spectroscopic ellipsometry (SE) characterization. Based on Tauc-Lorentz (TL) model, the optical constants of ZnO films were tentatively extracted in the photon energy ranging from 1.5 to 6.0 eV. Analyses by XRD and SE revealed that the oxygen partial pressure had effect on the orientation of the ZnO films, the surface morphology, the packing density, and the interfacial layers. And the relationship between crystallinity and interfacial layer, as well as the relationship between surface roughness and packing density was discussed. All these had a significant impact on the optical properties illustrated by SE analysis. 相似文献
16.
介绍了利用电子束蒸发技术在蓝宝石光纤端面上生长具有良好表面形貌和晶体结构的ZnO薄膜方法.不同测试温度(室温至773 K)条件下的透射光谱显示,蒸镀在蓝宝石光纤端面上的ZnO薄膜,其光学吸收边随温度升高而发生红移现象,且禁带宽度和热力学温度之间满足Eg(T)=340-491×10-4T的关系.这为今后进一步利用ZnO薄膜的禁带宽度检测相应的环境温度,研制以ZnO薄膜为敏感材料的新型宽量程光纤温度传感器打下了良好的基础.
关键词:
ZnO薄膜
蓝宝石光纤
光学吸收边
光纤温度传感器 相似文献
17.
Effective electromagnetic properties of honeycomb substrate coated with dielectric or magnetic layer
L. Liu C. Z. Fan N. B. Zhu Z. Y. Zhao R. P. Liu 《Applied Physics A: Materials Science & Processing》2014,116(3):901-905
Effective electromagnetic properties of aramid honeycomb board coated with a layer of multi-wall carbon nanotube or iron flakes composites were measured with waveguide method from 4 to 12 GHz. It was proved that homogenization theory could predict the effective permittivity or permeability of the honeycomb composites with good accuracy. The coated honeycomb composites of relatively high permittivity and permeability could potentially be used to develop dielectric or magnetic substrate for shielding layer or absorbing structures working at microwave frequencies. 相似文献
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19.
通过脉冲激光沉积技术制备了超导转变温度约为12 K的FeSe0.4Te0.6超导薄膜,测量了该薄膜晶体结构和在磁场(0-12 T)下的电输运性质。分别用传统的Arrhenius Plots和一种更精确的关系对薄膜的TAFF区的热激活能进行了分析,得到激活能对磁场和温度的指数关系;对两种方法分析结果分析比较,发现第二种方法的分析结果更符合FeSe0.4Te0.6超导薄膜的测量结果。估算了FeSe0.4Te0.6超导薄膜的玻璃态转变温度、上临界场Hc2(0)和相干长度。 相似文献
20.
The small size vortex-antivortex pairs proliferation in a type-II superconducting film is considered below T(c). The corresponding contribution to the free energy is calculated. It is shown that these fluctuations give the main temperature dependent contribution to the heat capacity of the superconducting film in the sufficiently large interval of temperatures below the transition point. 相似文献