Microstructural analysis of the compatibility of solution deposited buffer layers with the TFA process for YBCO

2000 ◽  
Vol 659 ◽  
Author(s):  
K. Salama ◽  
S. Sathyamurthy ◽  
M. Mironova
Keyword(s):  
Buffer Layer ◽  
Critical Current ◽  
Strontium Titanate ◽  
Surface Defects ◽  
Microstructural Analysis ◽  
Buffer Layers ◽  
Barium Zirconate ◽  
Chemical Compatibility ◽  
Superconducting Properties ◽  
Current Densities

ABSTRACTIn this paper, the feasibility of applying solution deposition processes for the fabrication of coated conductors has been explored. The crystal and chemical compatibility of the buffer layers processed using metalorganic decomposition with the Y123 deposition using the trifluoroacetate process has been studied. Two buffer layer materials have been used, namely, barium zirconate and strontium titanate. The measured superconducting properties of these conductors were correlated with the microstructure observed on these samples using SEM and cross-sectional TEM. In case of barium zirconate buffer layers, though there exists a very good structural and chemical compatibility between the buffer layer and the Y123, the presence of surface defects in the buffer layer causes compositional heterogeneity and randomly oriented grains in the Y123 film. This leads to poor superconducting properties. In case of strontium titanate buffer layers, due to the excellent crystal and chemical compatibility, and the absence of surface defects, high critical current densities (of the order of 106A/cm2 at 77K and self field) were obtained. However, TEM cross section studies reveals the presence of a significant portions of a-oriented Y123 crystallites which could lead to lower critical current densities. Further studies of the TFA process is required to eliminate the occurrence of a-oriented Y123 in the microstructure. This could lead to further improvements in the properties.

Crystalline Qualities and Critical Current Densities of As-Grown Ba2YCu3OxThin Films on Silicon with Buffer Layers

1990 ◽  
Vol 29 (Part 2, No. 6) ◽  
pp. L955-L957 ◽  
Author(s):  
Hiroaki Myoren ◽  
Yukio Nishiyama ◽  
Naokazu Miyamoto ◽  
Yasuaki Kai ◽  
Yasushi Yamanaka ◽  
...  
Keyword(s):  
Critical Current ◽  
Buffer Layers ◽  
Current Densities

YBCO Bulk Superconductors with Sm Addition

2017 ◽  
Vol 891 ◽  
pp. 483-488 ◽  
Author(s):  
Daniela Volochová ◽  
Vitaliy Antal ◽  
Jozef Kováč ◽  
Pavel Diko
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Superconducting Properties ◽  
Ybco Bulk ◽  
Pinning Centers ◽  
Bulk Superconductors ◽  
Powder Addition ◽  
Current Densities ◽  
Precursor Powders

The influence of Sm addition on the microstructure and superconducting properties of Y-Ba-Cu-O (YBCO) bulk superconductors has been studied. Precursor powders YBa2Cu3O7-δ (Y-123), Y2O3 and CeO2 were enriched with different amounts of SmBa2Cu3Oy (Sm-123) or Sm2O3 powders with the aim to increase critical current density, Jc,by introducing additional pinning centers. YBCO bulk superconductors with SmBa2Cu3Oy (Y123-Sm) or Sm2O3 (Y123-SmO) powder addition were prepared by the optimized top seeded melt growth process in the form of single grains. Microstructure analysis revealed that Sm2O3 addition leads to a higher amount of smaller Y2BaCuO5 (Y-211) particles, what is related to high critical current densities (Jc ~ 7 x 104 A/cm2) of the YBCO samples with Sm2O3 addition in low magnetic fields. The effect of Sm addition in the form of SmBa2Cu3Oy as well as Sm2O3 powder on Y2BaCuO5 particle size, critical temperature, Tc, and critical current density, Jc, is reported.

The RABiTS Approach: Using Rolling-Assisted Biaxially Textured Substrates for High-Performance YBCO Superconductors

MRS Bulletin ◽  
2004 ◽  
Vol 29 (8) ◽  
pp. 552-561 ◽  
Author(s):  
Amit Goyal ◽  
M. Parans Paranthaman ◽  
U. Schoop
Keyword(s):  
Critical Current ◽  
High Performance ◽  
Thermomechanical Processing ◽  
Cost Effective ◽  
Epitaxial Films ◽  
Buffer Layers ◽  
Ybco Films ◽  
Biaxial Texture ◽  
Ybco Superconductors ◽  
Current Densities

AbstractThis article provides an overview of the fabrication of epitaxial, biaxially aligned buffer layers on rolling-assisted biaxially textured substrates (RABiTS) as templates for YBCO films carrying high critical current densities.The RABiTS technique uses standard thermomechanical processing to obtain long lengths of flexible, biaxially oriented substrates with smooth surfaces.The strong biaxial texture of the metal is conferred to the superconductor by the deposition of intermediate metal and/or oxide layers that serve both as a chemical and a structural buffer.Epitaxial YBCO films with critical current densities exceeding 3 106A/cm2at 77K in self-field have been grown on RABiTS using a variety of techniques and demonstrate magnetic-field-dependent critical current values that are similar to those of epitaxial films on single-crystal ceramic substrates.The RABiTS architecture most commonly used consists of a CeO2 (sputtered)/YSZ (sputtered)/Y203 (e-beam)/Ni-W alloy.The desired texture of the base metal has been achieved in 100 m lengths and 10cm widths.Scaleable and cost-effective techniques are also being pursued to deposit the epitaxial multilayers.The results discussed here demonstrate that this technique is a viable route for the fabrication of long lengths of high-critical-current-density wire capable of carrying high currents in magnetic fields and at temperatures accessible by cooling with relatively inexpensive liquid nitrogen (up through the 77K range).

Lanthanum zirconate: A single buffer layer processed by solution deposition for coated conductor fabrication

2002 ◽  
Vol 17 (9) ◽  
pp. 2181-2184 ◽  
Author(s):  
S. Sathyamurthy ◽  
M. Paranthaman ◽  
H-Y. Zhai ◽  
H. M. Christen ◽  
P. P. Martin ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Low Cost ◽  
Sol Gel ◽  
Single Layer ◽  
Coated Conductors ◽  
Buffer Layers ◽  
Solution Deposition ◽  
Sol Gel Process ◽  
Current Densities ◽  
First Time

A single layer of La2Zr2O7 (LZO), deposited on textured Ni and Ni–1.7% Fe–3% W (Ni–W) tapes by a low-cost sol-gel process, is used as buffer layer for the growth of YBa2Cu3O7−δ (YBCO) coated conductors. It is shown for the first time that such single buffer layers can be used for the deposition of YBCO yielding critical current densities (Jc) that are comparable to those typically obtained using CeO2/YSZ/Y2O2 trilayers on identical substrates, i.e., in excess of 1 MA/cm2 at 77 K and self-field. The properties of the YBCO films and the dependence of Jc on thickness of the LZO layer are investigated.

Epitaxial Relationships of the a-Axis Oriented YBa2Cu3O7-x Thin Films on the PrBa2Cu3O7-xTx Buffered SrTiO3(100) by two Step PLD

1994 ◽  
Vol 341 ◽  
Author(s):  
Gun Yong Sung ◽  
Jeong Dae Suh ◽  
Sahn Nahm
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Volume Fraction ◽  
Buffer Layers ◽  
Laser Deposition ◽  
Superconducting Properties ◽  
Ybco Thin Film ◽  
Axis Orientation ◽  
Ybco Thin Films ◽  
Zero Resistance

AbstractAn a-axis oriented YBa2Cu3O7-x (YBCO) thin film exhibiting zero resistance at 83 K and critical current density of 7.9x103 A/cm2 at 62 K was obtained on an 180 nm - thick PrBa2Cu3 O7-xx(PBCO) buffered SrTiO3(100) substrate by two step pulsed laser deposition (PLD). The volume fraction of a-axis orientation and the crystallinity(Xmin) of the 150 nm-thick YBCO thin films were increased with increasing the thickness of PBCO buffer layer, which was varied friom 0 nm to 180 nm. It is concluded that the thickness of PBCO buffer layer is one of the important parameters to control the structural and superconducting properties of the a-axis oriented YBCO thin films using the PBCO buffer layers.

scholarly journals Approaching the ultimate superconducting properties of (Ba,K)Fe2As2 by naturally formed low-angle grain boundary networks

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Kazumasa Iida ◽  
Dongyi Qin ◽  
Chiara Tarantini ◽  
Takafumi Hatano ◽  
Chao Wang ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ion Irradiation ◽  
Microstructural Analysis ◽  
Grain Boundary Engineering ◽  
Superconducting Properties ◽  
Columnar Grains ◽  
Strong Pinning

AbstractThe most effective way to enhance the dissipation-free supercurrent in the presence of a magnetic field for type II superconductors is to introduce defects that act as artificial pinning centers (APCs) for vortices. For instance, the in-field critical current density of doped BaFe2As2 (Ba122), one of the most technologically important Fe-based superconductors, has been improved over the last decade by APCs created by ion irradiation. The technique of ion irradiation has been commonly implemented to determine the ultimate superconducting properties. However, this method is rather complicated and expensive. Here, we report a surprisingly high critical current density and strong pinning efficiency close to the crystallographic c-axis for a K-doped Ba122 epitaxial thin film without APCs, achieving performance comparable to ion-irradiated K-doped Ba122 single crystals. Microstructural analysis reveals that the film is composed of columnar grains with widths of approximately 30–60 nm. The grains are rotated around the b- (or a-) axis by 1.5° and around the c-axis by −1°, resulting in the formation of low-angle grain boundary networks. This study demonstrates that the upper limit of in-field properties reached in ion-irradiated K-doped Ba122 is achievable by grain boundary engineering, which is a simple and industrially scalable manner.

Fabrication of high Tc Superconducting Films with Diffusion Barriers

1987 ◽  
Vol 99 ◽  
Author(s):  
C. T. Ghien ◽  
Gang Xiao ◽  
M. Z. Cieplak ◽  
A. Bakhshai ◽  
A. Gavrin ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Meissner Effect ◽  
Superconducting Films ◽  
Diffusion Barriers ◽  
Buffer Layers ◽  
High Temperature Annealing ◽  
Superconducting Properties ◽  
High Tc ◽  
Effective Current ◽  
High Transition

Superconducting YBa2Cu3O; thin films have been prepared by magnetron sputtering onto [100] single crystal MgO with and without an Au buffer layer. All samples show high transition temperatures (82–87 K). The use of an Au buffer layer significantly improves the superconducting properties, particularly the Meissner effect and critical current density (3.3×106A/cm2 at 2 K and 3.5×104A/cm2 at T=77 K). The Au buffer layers remain metallic after high temperature annealing in an oxygen atmosphere, and may thus serve as effective current shunts.

scholarly journals Engineered Microstructures and Transport Properties in YBCO Coated Conductors

2001 ◽  
Vol 689 ◽  
Author(s):  
T. G. Holesinger ◽  
B. J. Gibbons ◽  
J. Y. Coulter ◽  
S. R. Foltyn ◽  
J. R. Groves ◽  
...  
Keyword(s):  
Transport Properties ◽  
Buffer Layer ◽  
Critical Current ◽  
Film Structure ◽  
Coated Conductors ◽  
Superconducting Film ◽  
Coated Conductor ◽  
Layer Material ◽  
Current Densities ◽  
Ybco Coated Conductors

ABSTRACTEach process used to deposit or make the bi-axially textured template, buffer layer(s), and the superconductor in a coated conductor creates interfaces along which defects or interfacial reactions may result. These defects can be additive and propagate through the entire film structure to affect the growth and properties of the superconducting film. Defects within the films and their corresponding transport properties have been correlated with the differences in the thickness of the underlying buffer layer material. This knowledge can be used to control and engineer the structure of the coated conductor to maximize critical current densities.

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.

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.

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