MOCVD of Heavily-Doped 25 mol.% Zr-Added (Gd, Y)Ba2Cu3O7-δ Coated Conductors

Gharahcheshmeh, Meysam Heydari; Galstyan, Eduard; Kukunuru, Jaideep; Katta, Rahul; Majkic, Goran; Li, Xiaofen; Selvamanickam, V.

doi:10.1109/tasc.2017.2660768

Cited by 15 publications

(6 citation statements)

References 14 publications

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“…While in-plane mismatch accommodation is the focus of this study, the elastic mismatch along the REBCO c-axis is an equally important aspect of film growth and nanorod self-assembly. We have reported earlier that the same metric, (Ba + Zr)/Cu, has a considerable effect on c-axis lattice mismatch between BZO and REBCO [48,61,63]. Multiple studies have reported presence of dense arrays of REBCO 124/248 type, 223 and other stacking faults [54,[83][84][85][86][87][88][89][90][91], and we have regularly observed the same features, as can also be seen in figure 2(d).…”

Section: In-plane Strain Accommodationsupporting

confidence: 84%

“…In the following, we present the composition as (Ba + Zr)/Cu ratio, for the reasons of the previously found strong correlation of in-field performance and other characteristics with this metric, as well as for easy cross-comparisons [15,48,61]. The fully compensated case corresponds to (Ba + Zr)/Cu = (2.15 + 0.15)/3 = 0.767, and the examined samples can be thought of as samples centered around nominal composition of RE 1.3 Ba 2+x Cu 3 + 0.15 Zr, with variation in Ba excess/deficiency content, x.…”

Section: Resultsmentioning

confidence: 99%

“…The striking effect of nanorods on flux pinning has sparked intense research on in-field performance optimization and mechanisms of self-assembly, including strain mismatch, growth kinetics and other aspects [5,15,[17][18][19][20][21][22][23]. The studies report widely varying nanorod landscapes, matching field, crystallographic texture, lattice parameters, critical temperature (T c ), self-field and in-field critical current (I c ), angular in-field I c dependence, size and density of nanorods, their angular splay distribution, and other relevant parameters [1,9,13,15,19,22,41,42,48,51,[61][62][63][64][65][66][67][68][69][70][71][72][73]. The level of improvement of in-field performance has been significant, with drastic increase in performance over a wide range of operating regimes, e.g.…”

Section: Introductionmentioning

confidence: 99%

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New insight into strain and composition of BaZrO₃ nanorods in REBCO superconductor

Majkic

Jeong

Yun

et al. 2021

Supercond. Sci. Technol.

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We report on strain and composition effects associated with growth of self-assembled BaZrO 3 (BZO) nanorods in REBa 2 Cu 3 O 7−δ (REBCO) superconductors (RE = rare earth = Y and Gd), which have a profound effect on flux pinning and in-field critical current performance. The a-b plane mismatch between BZO and REBCO is never fully coherently accommodated. Instead, the nanorods always assume a size at least one unit cell smaller than the corresponding 'hole' in the REBCO matrix, thus providing deep minima of in-plane mismatch strain. Next, we show that the nominal BZO nanorods are in fact solid solution Ba 2+ (Zr 4+ 1−z RE 3+ z )O 3−δ perovskite, thus strongly affecting the stoichiometry and relative amounts of REBCO and BZO. We demonstrate that by varying only the Ba content in the nominal composition of 15 mol.% BZO + REBCO, the unit cell density of BZO can be tuned from 5% to 23%, and the linear density of RE 2 O 3 (REO) precipitates from 18 to 1 µm −1 . The results explain the wide range of pinning performances observed for the same nominal amount of Zr addition and provide insight into the mechanisms behind the complex phenomenon of growth of nanorods by self-assembly in REBCO superconductors.

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Section: In-plane Strain Accommodationsupporting

confidence: 84%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New insight into strain and composition of BaZrO₃ nanorods in REBCO superconductor

Majkic

Jeong

Yun

et al. 2021

Supercond. Sci. Technol.

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“…One particular aspect of interest was maximizing the lift factor (LF), defined as the ratio of I c at desired temperature/field and I c value at 77 K, self-field itself 12–15 . Extensive optimization of the REBCO-BZO system has been done using MOCVD, in terms of dopant concentration, film microstructure, growth conditions and composition to achieve high in-field performance 13,16–18 . However, common to most REBCO film growth techniques, J c was typically found to strongly deteriorate with thickness 19–21 .…”

Section: Introductionmentioning

confidence: 99%

Over 15 MA/cm2 of critical current density in 4.8 µm thick, Zr-doped (Gd,Y)Ba2Cu3Ox superconductor at 30 K, 3T

Majkic

Pratap

et al. 2018

Sci Rep

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An Advanced MOCVD (A-MOCVD) reactor was used to deposit 4.8 µm thick (Gd,Y)BaCuO tapes with 15 mol% Zr addition in a single pass. A record-high critical current density (Jc) of 15.11 MA/cm2 has been measured over a bridge at 30 K, 3T, corresponding to an equivalent (Ic) value of 8705 A/12 mm width. This corresponds to a lift factor in critical current of ~11 which is the highest ever reported to the best of author’s knowledge. The measured critical current densities at 3T (B||c) and 30, 40 and 50 K, respectively, are 15.11, 9.70 and 6.26 MA/cm2, corresponding to equivalent Ic values of 8705, 5586 and 3606 A/12 mm and engineering current densities (Je) of 7068, 4535 and 2928 A/mm2. The engineering current density (Je) at 40 K, 3T is 7 times higher than that of the commercial HTS tapes available with 7.5 mol% Zr addition. Such record-high performance in thick films (>1 µm) is a clear demonstration that growing thick REBCO films with high critical current density (Jc) is possible, contrary to the usual findings of strong Jc degradation with film thickness. This achievement was possible due to a combination of strong temperature control and uniform laminar flow achieved in the A-MOCVD system, coupled with optimization of BaZrO3 nanorod growth parameters.

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“…CVD, especially metal–organic CVD (MOCVD) method, is widely used in the semiconductor industry and high‐temperature superconductors for the growth of thin films of inorganic materials. Uniformity, thickness control, purity, and systematic control over material properties through process conditions are major factors for the broad adoption of this approach.…”

Section: Optimizing the Properties Of Ocvd Cpmentioning

confidence: 99%

Device Fabrication Based on Oxidative Chemical Vapor Deposition (oCVD) Synthesis of Conducting Polymers and Related Conjugated Organic Materials

Gharahcheshmeh

Gleason

2018

Adv Materials Inter

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lightweight, wearable, and stretchable properties of CPs relative to traditional materials highlight the areas where CPs may find their niche in modern devices. [2] The fabrication of uniform CPs in large scale with high throughput roll-to-roll process is of great importance in industrial sectors. To achieve this purpose, chemical vapor deposition (CVD) along with other vapor deposition methods are the promising approaches to expedite the commercialization process of CPs in large-scale applications.For polymers which dissolve, films can be formed by solution-based methods such as dip-coating and spin-coating. However, CPs, particularly those formed from unfunctionalized monomers, are often insoluble or require solvents which are unsafe and costly to use. The lack of solubility is typically associated with a rigid backbone structure that promotes crystallite formation. As a result, dissolution requires overcoming the associated enthalpy of crystallization.The need for solubilizing polymers is eliminated by employing CVD as the thin film formation technique. A variety of different CVD processes have been developed for vapor phase reactants to undergo similar polymerization mechanisms as those reported for solution synthesis. [3] These include CVD polymer methods for chain growth by free radical or cationic initiation, or by condensation polymerization. For most conjugated macromolecules, the desired variant of the CVD method needs to mimic the step-growth polymerization mechanism in order to obtain optimized properties, such as electrical conductivity. This motivated the invention of oxidative CVD (oCVD) in which the vacuum chamber design, strategy for reactant vapor introduction, and process conditions are optimized for step-growth polymerization. Vapor deposition methods which are not mechanistically motivated, such as thermal evaporation, pulsed laser deposition, and plasma-enhanced CVD, can result in conjugated polymer films having properties that are insufficient for integration into many types of devices. Thus, one major significance of achieving conjugated polymers having highly desirable characteristics by oCVD is the ability to fabricate state-of-the-art optoelectronic and energy storage devices.The oCVD process is a single-step method to convert vapor phase monomers, along with vapors of oxidant, into thin CP films. [3,4] At the surface of the substrate, step-growth Conducting polymers (CPs) combine electronic conductivity, optical transparency, and mechanical flexibility compatible with lightweight substrates. Due to these features CPs exhibit promising performance for a wide range of applications including electronic, optoelectronic, electrochemical, optochemical, and energy storage and harvesting devices. Fabrication of high-quality CPs thin film in a large scale is of high demand in multiple industrial sectors. Chemical vapor deposition (CVD) is a promising approach for scale-up and commercialization of CPs in large-scale thin film applications by a roll-to-roll process. The CVD technique is a versati...

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MOCVD of Heavily-Doped 25 mol.% Zr-Added (Gd, Y)Ba2Cu3O7-δ Coated Conductors

Cited by 15 publications

References 14 publications

New insight into strain and composition of BaZrO₃ nanorods in REBCO superconductor

New insight into strain and composition of BaZrO₃ nanorods in REBCO superconductor

Over 15 MA/cm2 of critical current density in 4.8 µm thick, Zr-doped (Gd,Y)Ba2Cu3Ox superconductor at 30 K, 3T

Device Fabrication Based on Oxidative Chemical Vapor Deposition (oCVD) Synthesis of Conducting Polymers and Related Conjugated Organic Materials

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MOCVD of Heavily-Doped 25 mol.% Zr-Added (Gd, Y)Ba2Cu3O7-δ Coated Conductors

Cited by 15 publications

References 14 publications

New insight into strain and composition of BaZrO3 nanorods in REBCO superconductor

New insight into strain and composition of BaZrO3 nanorods in REBCO superconductor

Over 15 MA/cm2 of critical current density in 4.8 µm thick, Zr-doped (Gd,Y)Ba2Cu3Ox superconductor at 30 K, 3T

Device Fabrication Based on Oxidative Chemical Vapor Deposition (oCVD) Synthesis of Conducting Polymers and Related Conjugated Organic Materials

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Product

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New insight into strain and composition of BaZrO₃ nanorods in REBCO superconductor

New insight into strain and composition of BaZrO₃ nanorods in REBCO superconductor