scholarly journals The Influence of Surface Morphology of Buffer Layer on the Critical Current Density in YBCO Coated Conductors

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jie Xiong ◽  
Yudong Xia ◽  
Fei Zhang ◽  
Yan Xue ◽  
Kai Hu ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Critical Current Density ◽  
Buffer Layer ◽  
Critical Current ◽  
Current Density ◽  
Coated Conductors ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Ybco Films ◽  
Surface Morphologies

1 μm-thickYBa2Cu3O7-δ(YBCO) films were grown on the Y2O3/yttria stabilized zirconia (YSZ)/CeO2buffer layers with different surface morphologies using direct-current sputtering. The critical current density (Jc) value of YBCO was 1.1 MA/cm2when the root mean square surface roughness (Rrms) of the buffer layer was 2.5 nm. As theRrmsof the buffer layer increased to 15 nm, theJcdecreased to 0.3 MA/cm2. X-ray diffraction and scanning electron microscopy showed the strong relevance of the evolution of the structure and surface morphologies of YBCO films with the buffer layer of differentRrms. A model was proposed to explain the influence of surface morphology on the superconducting properties of YBCO films.

Fabrication of High Jc YBa2Cu3O7-δ Coated Conductors Using Sol-Gel Buffer Layers On Nickel and Nickel Alloy Substrates

2001 ◽  
Vol 689 ◽  
Author(s):  
S. Sathyamurthy ◽  
M. Paranthaman ◽  
B. W. Kang ◽  
H. Y. Zhai ◽  
T. Aytug ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Sol Gel ◽  
Rf Sputtering ◽  
Cube Texture ◽  
Dip Coating ◽  
Coated Conductors ◽  
Buffer Layers ◽  
Ybco Films

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.

Comparative Study of Thickness Dependence of Critical Current Density of Yba2Cu3O7–δ on (100) SrTiO3 and on Rolling-assisted Biaxially Textured Substrates

2002 ◽  
Vol 17 (7) ◽  
pp. 1750-1757 ◽  
Author(s):  
B. W. Kang ◽  
A. Goyal ◽  
D. F. Lee ◽  
J. E. Mathis ◽  
E. D. Specht ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Critical Current Density ◽  
Film Thickness ◽  
Comparative Study ◽  
Critical Current ◽  
Current Density ◽  
Pulsed Laser ◽  
Cube Texture ◽  
Laser Deposition ◽  
Ybco Films

We investigated the dependence of critical current density (Jc) on thickness of Yba2Cu3O7−δ (YBCO) films grown by pulsed laser deposition on (100) SrTiO3 (STO) and on rolling-assisted biaxially textured substrates (RABiTS). The thickness of YBCO films varied from 0.19 to 3 μm. The highest Jcs of 5.3 and 2.6 MA/cm2 at 77 K, self-field were obtained for 0.19-μm YBCO films on STO and RABiTS, respectively. Jc was found to decrease exponentially with YBCO thickness on both substrates. However, the results suggest different mechanisms are responsible for the Jc reduction in the two cases. On STO, growth of a-axis grains within c-axis films and broadening of the in-plane texture were observed in thick films. On RABiTS, degradation in cube texture as well as development of a porous surface morphology were found to correlate with film thickness.

Influence of Buffer Layer Surface Morphology on YBCO Critical Current Density Deposited on NiW Tapes

2011 ◽  
Vol 21 (3) ◽  
pp. 2924-2927 ◽  
Author(s):  
Yijie Li ◽  
Linfei Liu ◽  
Huaran Liu ◽  
Xiaokun Sun ◽  
Dan Hong ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Critical Current Density ◽  
Buffer Layer ◽  
Critical Current ◽  
Current Density ◽  
Layer Surface

Evidence for Extensive Grain Boundary Meander and Overgrowth of Substrate Grain Boundaries in High Critical Current Density ex Situ YBa2Cu3O7−x Coated Conductors

2005 ◽  
Vol 20 (8) ◽  
pp. 2012-2020 ◽  
Author(s):  
D.M. Feldmann ◽  
D.C. Larbalestier ◽  
T. Holesinger ◽  
R. Feenstra ◽  
A.A. Gapud ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Film Thickness ◽  
Critical Current ◽  
Current Density ◽  
Thick Films ◽  
Coated Conductors ◽  
Ex Situ ◽  
High Critical Current Density ◽  
Ybco Films

It has been generally accepted that YBa2Cu3O7−x (YBCO) films deposited on deformation textured polycrystalline metal tapes result in YBCO grain boundary (GB) networks that essentially replicate the GBs of the underlying substrate. Here we report that for thicker YBCO films produced by a BaF2 ex situ process, this is not true. Using electron backscatter diffraction combined with ion milling, we have been able to map the evolution of the YBCO grain structure and compare it to the underlying template in several coated conductors. For thin (≤0.5 μm) YBCO films deposited on rolling-assisted biaxially textured substrates (RABiTS), the YBCO GBs nearly directly overlap the substrate GBs. For 0.7–1.4 μm YBCO films, the GBs were found to meander along the substrate GBs and along the sample normal, with displacements several times the film thickness. In very thick films (2.5–2.9 μm), the YBCO grains can completely overgrow substrate grains and GBs, resulting in a substantial disconnection of the YBCO and substrate GB networks. Similar behavior is found for BaF2 ex situ YBCO films on ion-beam-assisted deposition-type templates. The ability of the YBCO to overgrow substrate grains and GBs is believed to be due to liquid-phase mediated laminar grain growth. Although the behavior of the YBCO GB networks changes with YBCO film thickness, the samples maintained high critical current density (Jc) values of >2 MA/cm2 for films up to 1.4 μm thick, and up to0.9 MA/cm2 for 2.5–2.9-μm-thick films.

scholarly journals О возможности изготовления мостиков YBCO с совершенной поверхностью, критической температурой более 88 K и плотностью критического тока до 5·10-=SUP=-6-=/SUP=- A/cm-=SUP=-2-=/SUP=-

2020 ◽  
Vol 62 (9) ◽  
pp. 1398
Author(s):  
Д.В. Мастеров ◽  
С.А. Павлов ◽  
А.Е. Парафин ◽  
Е.В. Скороходов
Keyword(s):  
Critical Temperature ◽  
Surface Morphology ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Growth Process ◽  
Ybco Films ◽  
Basic Parameters ◽  
Critical Current Density Jc ◽  
Electrophysical Parameters

In the fabrication of YBCO structures by traditional methods, as a rule, some compromise is reached, namely, films with acceptable morphology are used, but with reduced electrophysical parameters. In this paper, it is shown that YBCO bridges up to 4 microns wide with perfect surface morphology, i.e. free from defects, with a critical current density Jc ≥ 3106 A/cm2 at a temperature T = 77 K and a critical temperature Tс ≥ 88 K. can be obtained using the preliminary topology mask method. Moreover, the perfect morphology of the bridge surface, the values of the critical current density and the critical temperature are preserved even after repeated (additional) deposition of the YBCO layer on the structure with the preliminary topology mask. Based on the results obtained in a series of fifteen samples, it is concluded that, in contrast to the electrophysical characteristics, it is not enough to fix the standard (basic) parameters of the growth process for the stable implementation of the perfect surface morphology of YBCO films.

Crystalline Alignment and In-plane Texture Improvement of Buffer Layers Deposited on NiW Tapes

2011 ◽  
Vol 1308 ◽  
Author(s):  
Linfei Liu ◽  
Yijie Li ◽  
Huaran Liu ◽  
Xiaokun Song ◽  
Dan Hong ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Deposition Parameters ◽  
Current Densities ◽  
Diffraction Peaks ◽  
Deposition Conditions

ABSTRACTIn order to deposit YBCO coated conductor with high critical current densities on rolling assisted biaxially textured Ni-W tapes, this paper has systematically studied the influence of deposition conditions on the orientation, in-plane texture and surface morphology of buffers and superconducting layers. It was found that the crystalline alignment and the in-plane texture of cerium oxide cap-layers were well improved by optimizing deposition parameters. The full width at half maximum of phi-scan x-ray diffraction peaks were reduced from original values of 7-8 degrees to 5-6 degrees. A high critical current density of 4.6×106 A/cm2 has been achieved on optimized buffer layers. This value is comparable with the critical current density of YBCO thin films deposited on single crystalline substrates.

Preparation of InN by Means of AP-HCVD Using In Buffer Layers

2007 ◽  
Vol 1040 ◽  
Author(s):  
Hiroaki Yokoo ◽  
Naoki Wakiya ◽  
Naonori Sakamoto ◽  
Takato Nakamura ◽  
Hisao Suzuki
Keyword(s):  
Electrical Property ◽  
Surface Morphology ◽  
Buffer Layer ◽  
Atmospheric Pressure ◽  
Indium Nitride ◽  
Buffer Layers ◽  
Crystal Quality ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quality Surface

AbstractWe have grown indium nitride (InN) films using In buffer layer on an a-plane sapphire substrate under atmospheric pressure by halide CVD (AP-HCVD). Growth was carried out by two steps: deposition In buffer layer at 900 °C and subsequent growth of InN layer at 650 °C. In order to compare, we also grown InN films on an a-plane sapphire. The InN films are investigated on crystal quality, surface morphology and electrical property using high-resolution X-ray diffraction (HR-XRD), X-ray pole figure, scanning electron microscope (SEM), Hall measurement. The results show that the crystal quality, surface morphology and electrical property of InN films are improved by using In buffer layer.

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