High-Jc YBCO coatings on reel-to-reel dip-coated Gd2O3 seed buffer layers epitaxially fabricated on biaxially textured Ni and Ni-(3at%W-1.7at%Fe) alloy tapes

2001 ◽  
Vol 689 ◽  
Author(s):  
Tolga Aytug ◽  
M. Paranthaman ◽  
S. Sathyamurthy ◽  
B. W. Kang ◽  
D. B. Beach ◽  
...  

ABSTRACTA low-cost, non-vacuum reel-to reel dip-coating system has been used to continuously fabricate epitaxial Gd2O3 buffer layers on mechanically strengthened, biaxially textured Ni- (3at.%W-1.7at%Fe), defined as Ni-alloy, metal tapes. X-ray diffraction analysis of the seed Gd2O3 layers indicated that well textured films can be obtained at processing temperatures (Tp) between 1100 and 1175°C. Processing speed did not significantly affect the crystalline quality of the Gd2O3. Scanning electron microscopy revealed a continuous, dense and crack-free surface morphology for these dip-coated buffers. The Gd2O3 layer thickness led to remarkable differences in the growth characteristics of the subsequent YSZ and CeO2 layers deposited by rfmagnetron sputtering. Epitaxial YBCO films grown by pulsed laser deposition on the short prototype CeO2/YSZ/Gd2O3/Ni-(3at%W-1.7at%Fe) conductors yielded self-field critical current densities (Jc) as high as 1.2×106 A/cm2 at 77 K. Pure Ni tapes were used to asses the viability of dip-coated buffers for long length coated conductor fabrication. The YBCO films, grown on 80 cm long and 1 cm wide CeO2/YSZ/Gd2O3 buffered Ni tapes by the industrially scalable ex-situ BaF2 precursor process, exhibited end-to-end self-field Jc of 6.25×105 A/cm2 at 77 K.

2002 ◽  
Vol 17 (6) ◽  
pp. 1543-1549 ◽  
Author(s):  
S. Sathyamurthy ◽  
M. Paranthaman ◽  
T. Aytug ◽  
B. W. Kang ◽  
P. M. Martin ◽  
...  

Sol-gel processing of La2Zr2O7 (LZO) buffer layers on biaxially textured Ni–1.7% Fe–3% W alloy substrates using a continuous reel-to-reel dip-coating unit has been studied. The epitaxial LZO films obtained have a strong cube texture and uniform microstructure. The effects of increasing the annealing speed on the texture, microstructure, and carbon content retained in the film were studied. On top of the LZO films, epitaxial layers of yttria-stabilized zirconia and Ceria (CeO2) were deposited using rf sputtering, and YBa2Cu3Ox (YBCO) films were then deposited using pulsed laser deposition. Critical current densities (Jc) of 1.9 MA/cm2 at 77 K and self-field and 0.34 MA/cm2at 77 K and 0.5 T have been obtained on these films. These values are comparable to those obtained on YBCO films deposited on all-vacuum deposited buffer layers and the highest ever obtained using solution seed layers.


2002 ◽  
Vol 17 (9) ◽  
pp. 2193-2196 ◽  
Author(s):  
T. Aytug ◽  
M. Paranthaman ◽  
H. H. Zhai ◽  
H. H. Christen ◽  
S. Sathyamurthy ◽  
...  

Single, epitaxial buffer layers of insulating LaMnO3 (LMO) or conductive La0.7Sr0.3MnO3 (LSMO) have been grown by sputter deposition on biaxially textured Ni and Ni–alloy substrates. We report baseline investigations of their compatibility with the Yba2Cu3O7−δ (YBCO) coatings and demonstrate biaxially textured YBCO films grown by pulsed-laser deposition on these single-buffered tapes. Superconducting property characterizations revealed better properties for YBCO films on LMO-buffered tapes relative to those grown on LSMO layers. Self-field critical current densities (Jc) exceeding 1 × 106 A/cm2 at 77 K have been obtained for the YBCO (200 nm) films on LMO-buffer layers. These results offer prospects for the use of single, LMO-buffered metal tapes in the development of practical YBCO-coated conductors.


NANO ◽  
2018 ◽  
Vol 13 (05) ◽  
pp. 1850052
Author(s):  
Yuanyuan Zhou ◽  
Jianying Deng ◽  
Shimei Li ◽  
Zefeng Li

Core–shell Cu@Ni chains were successfully synthesized through a mild hydrothermal reaction. The morphology, structure and microwave electromagnetic properties of the composite were then characterized by X-ray diffraction, energy-dispersive spectroscopy, scanning electron microscopy and vector network analysis. The formation mechanisms of the core–shell structure and one-dimensional chains were ascribed to the varying redox potentials of Cu and Ni ions and the magnetic dipole–dipole attraction. Furthermore, a minimal reflection loss (RL) of [Formula: see text]20.7[Formula: see text]dB was observed at 9.6[Formula: see text]GHz with a thickness of 2.0[Formula: see text]mm and the effective absorption ([Formula: see text]10[Formula: see text]dB, 90% microwave attenuation) bandwidth can be adjusted between 5.2[Formula: see text]GHz and 16.6[Formula: see text]GHz for the thin absorber thickness of 2.0–4.0[Formula: see text]mm. The novel core–shell chain-like Cu@Ni alloy can be used as a promising absorbing material because it shows numerous features such as thin thickness, strong absorption, low cost and lightweight.


DYNA ◽  
2018 ◽  
Vol 85 (207) ◽  
pp. 192-197 ◽  
Author(s):  
Estrella Natali Borja-Goyeneche ◽  
Jhon Jairo Olaya-Florez

This work researches the influence of the nickel content on the structural and anticorrosive properties of ZrSiTiN films deposited by means of reactive co-sputtering on alloys of Ti6Al4V. The morphology and structure were analyzed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the chemical composition was identified via X-ray scattering spectroscopy (EDS). The corrosion resistance was studied using potentiodynamic polarization (PP) tests employing a 3.5% by weight NaCl solution. In the films, an increase of Ni up to 6.97 at% was observed, while in XRD the FCC phase of (Zr, Ti) N was identified, with a mixed orientation in planes (111) and (200), which tended to diminish with the increase of Ni. Finally, with the addition of Ni, the corrosion current densities were reduced from 5.56 𝑥 10−8 to 2.64 𝑥 10−9 𝐴/𝑐m2. The improvement in the corrosion resistance is due to the effect of the Ni on the microstructure of the system (Zr, Ti) N, which can improve the quality of the passive film and prevent crystalline defects and corrosion zones.


2009 ◽  
Vol 24 (4) ◽  
pp. 1446-1455 ◽  
Author(s):  
M. Coll ◽  
J. Gàzquez ◽  
R. Huhne ◽  
B. Holzapfel ◽  
Y. Morilla ◽  
...  

New advances toward microstructural improvement of epitaxial CeO2 films grown by chemical solution deposition and their use as buffer layers for YBa2Cu3O7 (YBCO) films are presented. We demonstrate that the degree of epitaxy and the fraction of (001) atomically flat surface area are controlled by the incorporation of tetravalent (Zr4+) or trivalent (Gd3+) cations into the ceria lattice. The degree of epitaxy has been investigated by means of Rutherford backscattering spectroscopy-channeling and reflection high-energy electron diffraction, and a new methodology is also presented to quantify the fraction of (001) atomically flat area from atomic force microscopy images. Results are further correlated with the superconducting properties, microstructure, and texture of YBCO films grown by the trifluoroacetate route. A comparison with pulsed laser deposition and YBCO films grown on the same ceria layers is also presented. This growth procedure has allowed us to obtain all chemical multilayer films with controlled microstructure and critical current densities above 4 MA cm−2 at 77 K.


2012 ◽  
Vol 569 ◽  
pp. 62-69
Author(s):  
Hui Zhou Liu ◽  
Jian Yang ◽  
Hua Zhang

High Tc superconducting tapes based on YBCO Coated Conductor have been extensively studied to develop the processing techniques for application. In this paper, two self-designed reel-to-reel deposition systems (Sputtering and PLD) were installed. Continuous deposition of multi-layer CeO2/YSZ/Y2O3 buffer layers were carried out on biaxially textured NiW substrate using reactive sputtering. YBCO films were coated on the CeO2/YSZ/Y2O3 buffered NiW substrate by continuous PLD subsequently. To achieve high current carrying capacities, combinations of various deposition conditions were explored. X-ray diffraction measurements show good in-plane and out-plane texture in buffer layers and YBCO films. The transition temperature of the YBCO was 89 K and the critical current is over 50 A at 77 K in 1 meter long YBCO tapes.


2009 ◽  
Vol 16 (01) ◽  
pp. 99-103 ◽  
Author(s):  
L. S. CHUAH ◽  
Z. HASSAN ◽  
H. ABU HASSAN

High-quality aluminum nitride ( AlN ) layers with full width at half maximum (FWHM) values of 11 arcmin were grown by plasma-assisted molecular-beam epitaxy on Si (111) substrates. AlN nucleation layers are being investigated for the growth of GaN on Si . Growth using AlN buffer layers leads to Al -polar films, with surfaces strongly dependent on the flux conditions used. Flat surfaces can be obtained by growing as Al -rich as possible, although Al droplets tend to form. Before starting the AlN growth, a few monolayers of Al are deposited on the substrate to avoid the formation of Si 3 N 4. X-ray diffraction (XRD) techniques were employed to determine the surface and structural quality of the layers. XRD revealed that monocrystalline AlN was obtained. Best AlN films were obtained at high substrate temperatures (875°C) and III/V ratios close to stoichiometry.


1996 ◽  
Vol 449 ◽  
Author(s):  
A. J. Drehman ◽  
P. W. Yip

ABSTRACTUsing reactive rf sputtering, we have grown (0001) oriented ZnO films in situ on heated c-axis sapphire substrates, that are promising, particularly in terms of surface roughness, as buffer layers for the subsequent epitaxial growth of III-V nitride films. We compare the effects of on-axis and off-axis sputter geometries on the film epitaxy and smoothness. We also examined the effect of substrate temperature on the growth and smoothness and quality of the film. X-ray diffraction was used to verify the hexagonal ZnO phase, its c-axis orientation and, qualitatively, the degree of its epitaxy. Atomic Force Microscopy (AFM) was used to determine the ZnO growth morphology and roughness. Our best films, obtained by off-axis sputter deposition, have a surface roughness of less than 1 nm.


1995 ◽  
Vol 10 (5) ◽  
pp. 1086-1090 ◽  
Author(s):  
J.H. Kroese ◽  
A.J. Drehrman ◽  
J.A. Horrigan

Thin films of Y-stabilized ZrO2 (YSZ) were deposited by RF diode sputtering on R-plane sapphire as a buffer layer for the deposition of YBa2Cu3O3 (YBCO). By increasing the partial pressure of oxygen in the sputter gas mixture from 20% to 50%, it was found that the substrate temperature required to obtain (100) oriented YSZ deposition could be lowered to 630 °C from 800 °C. This change is attributed to heating or mixing effects at the film surface, due to an increase in negative ion bombardment, which supplements the effects of external heating. Increases in the partial pressure of oxygen beyond 50% were found to be counterproductive. YBCO films, deposited on the YSZ buffer layers via magnetron sputtering, showed c-axis orientation and transition temperatures of 82 K. Orientation of both the YSZ and YBCO films was confirmed by x-ray diffraction and SEM characterization.


2001 ◽  
Vol 689 ◽  
Author(s):  
S. Sathyamurthy ◽  
M. Paranthaman ◽  
B. W. Kang ◽  
H. Y. Zhai ◽  
T. Aytug ◽  
...  

Sol-gel processing of La2Zr2O7 (LZO) buffer layers on biaxially textured Ni-3 at.% W alloy substrates using a continuous reel-to-reel dip-coating unit has been studied. The epitaxial LZO films obtained have a strong cube texture and uniform microstructure. The effect of increasing the annealing speed on the texture, microstructure and the carbon content retained in the film were studied. On top of the LZO films, epitaxial layers of Yttria Stabilized Zirconia (YSZ) and Ceria (CeO2) were deposited using rf sputtering, and YBa2Cu3Ox (YBCO) films were then deposited using Pulsed Laser Deposition (PLD). A critical current density (Jc) of 1.9 MA/cm2 at 77K and self-field and 0.34 MA/cm2 at 77K and 0.5T have been obtained on these films. These values are comparable to those obtained on YBCO films deposited on all-vacuum deposited buffer layers, and are the highest ever obtained using solution seed layers. The use of all-solution buffers for coated conductor processing has also been explored. A critical current density of 1.1 MA/cm2 at 77 K and self-field was obtained on YBCO films grown be PLD on LZO buffered nickel substrates.


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