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Title: Substrate Surface Decoration With CeO2 Nanoparticles: An Effective Method for Improving Flux Pinning in YBa2Cu3O7 Films

Abstract

We have demonstrated improved critical current density, J{sub c}, in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films through a controlled study of substrate surface modifications with nano-sized second-phase pre-formed CeO{sub 2} particles. Nanoparticles were applied to single crystal SrTiO{sub 3} surfaces using suspension-based techniques prior to YBCO film growth. With the introduction of CeO{sub 2} nanoparticles, YBCO films showed more robust field dependence at intermediate fields (J{sub c} {infinity} B{sup -{infinity}}), where a smaller power law exponent of {alpha} {approx} 0.3 is obtained. The self-field J{sub c}(77 K, B{parallel}c) values of the YBCO films on reference and CeO{sub 2} modified substrates are 1.1 and 1.9 MA/cm2; and at 1 Tesla 0.1 and 0.52 MA/cm2, respectively. Consistent with this {alpha}-value, angular field dependent J{sub c} and transmission electron microscopy studies indicate the presence of c-axis aligned correlated defects in these modified samples.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [2];  [2];  [1];  [1]
  1. ORNL
  2. Columbia University
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
OE USDOE - Office of Electric Transmission and Distribution
OSTI Identifier:
931682
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: Applied Superconductor Conference, Seattle, WA, USA, 20060827, 20060901
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; SUBSTRATES; SURFACE PROPERTIES; NANOSTRUCTURES; CERIUM OXIDES; CURRENT DENSITY; CRITICAL CURRENT; MAGNETIC FLUX; YTTRIUM OXIDES; BARIUM OXIDES; COPPER OXIDES

Citation Formats

Aytug, Tolga, Paranthaman, Mariappan Parans, Gapud, Albert Agcaoili, Kang, Sukill, Varela del Arco, Maria, Martin, Patrick M, Raitano, J. M., Chan, S. W., Thompson, James R, and Christen, David K. Substrate Surface Decoration With CeO2 Nanoparticles: An Effective Method for Improving Flux Pinning in YBa2Cu3O7 Films. United States: N. p., 2007. Web.
Aytug, Tolga, Paranthaman, Mariappan Parans, Gapud, Albert Agcaoili, Kang, Sukill, Varela del Arco, Maria, Martin, Patrick M, Raitano, J. M., Chan, S. W., Thompson, James R, & Christen, David K. Substrate Surface Decoration With CeO2 Nanoparticles: An Effective Method for Improving Flux Pinning in YBa2Cu3O7 Films. United States.
Aytug, Tolga, Paranthaman, Mariappan Parans, Gapud, Albert Agcaoili, Kang, Sukill, Varela del Arco, Maria, Martin, Patrick M, Raitano, J. M., Chan, S. W., Thompson, James R, and Christen, David K. Mon . "Substrate Surface Decoration With CeO2 Nanoparticles: An Effective Method for Improving Flux Pinning in YBa2Cu3O7 Films". United States. doi:.
@article{osti_931682,
title = {Substrate Surface Decoration With CeO2 Nanoparticles: An Effective Method for Improving Flux Pinning in YBa2Cu3O7 Films},
author = {Aytug, Tolga and Paranthaman, Mariappan Parans and Gapud, Albert Agcaoili and Kang, Sukill and Varela del Arco, Maria and Martin, Patrick M and Raitano, J. M. and Chan, S. W. and Thompson, James R and Christen, David K},
abstractNote = {We have demonstrated improved critical current density, J{sub c}, in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films through a controlled study of substrate surface modifications with nano-sized second-phase pre-formed CeO{sub 2} particles. Nanoparticles were applied to single crystal SrTiO{sub 3} surfaces using suspension-based techniques prior to YBCO film growth. With the introduction of CeO{sub 2} nanoparticles, YBCO films showed more robust field dependence at intermediate fields (J{sub c} {infinity} B{sup -{infinity}}), where a smaller power law exponent of {alpha} {approx} 0.3 is obtained. The self-field J{sub c}(77 K, B{parallel}c) values of the YBCO films on reference and CeO{sub 2} modified substrates are 1.1 and 1.9 MA/cm2; and at 1 Tesla 0.1 and 0.52 MA/cm2, respectively. Consistent with this {alpha}-value, angular field dependent J{sub c} and transmission electron microscopy studies indicate the presence of c-axis aligned correlated defects in these modified samples.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

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  • Interfacial engineering via nanoparticle substrate surface decoration has been extended to coated conductor templates. Preformed BaTiO{sub 3} and BaZrO{sub 3} nanoparticles were applied to substrate surfaces, prior to YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) deposition, by using a scalable and inexpensive technique of solution-based suspension. Compared to untreated reference samples, nanodecoration yields improved in-field critical current density (J{sub c}) as well as strong correlated pinning along the c-axis direction of the YBCO film. Accordingly, a much reduced falloff of J{sub c} with magnetic field strength was observed in all of the modified samples. In addition, scaling behavior of the normalized volumemore » pinning force density (F{sub p}) with respect to temperature provided insight as to the differences in flux pinning mechanisms dependent on the decoration technique. Finally, with these results our earlier proof-of-concept demonstrations on nanoparticle modified single crystal substrates were replicated on technological substrates, pointing to the versatility of this simple technique for realization of enhanced high temperature superconductor performance.« less
  • Interfacial engineering via nanoparticle substrate surface decoration has been extended to coated conductor templates. Preformed BaTiO{sub 3} and BaZrO{sub 3} nanoparticles were applied to substrate surfaces, prior to YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) deposition, by using a scalable and inexpensive technique of solution-based suspension. Compared to untreated reference samples, nanodecoration yields improved in-field critical current density (J{sub c}) as well as strong correlated pinning along the c-axis direction of the YBCO film. Accordingly, a much reduced falloff of J{sub c} with magnetic field strength was observed in all of the modified samples. In addition, scaling behavior of the normalized volumemore » pinning force density (F{sub p}) with respect to temperature provided insight as to the differences in flux pinning mechanisms dependent on the decoration technique. Finally, with these results our earlier proof-of-concept demonstrations on nanoparticle modified single crystal substrates were replicated on technological substrates, pointing to the versatility of this simple technique for realization of enhanced high temperature superconductor performance.« less
  • Technological applications of high temperature superconductors (HTS) require high critical current density, Jc, under operation at high magnetic field strengths. This requires effective flux pinning by introducing artificial defects through creative processing. In this work, we generated correlated disorder for strong vortex pinning in the YBa2Cu3O7- (YBCO) films by replacing the standard LaMnO3 (LMO) cap buffer layers in ion beam assisted deposited MgO templates with LMO:MgO composite films. Such films revealed formation of two phase-separated, but at the same time vertically aligned, self-assembled composite nanostructures that extend throughout the entire thickness of the film. Measurements of magnetic-field orientation-dependent Jc ofmore » YBCO coatings deposited on these nanostructured cap layers showed correlated c-axis pinning and improved in-field Jc performance compared to those of YBCO films deposited on standard LMO buffers. The present results demonstrate feasibility of novel and potentially practical approaches in the pursuit of more efficient, economical, and high performance superconducting devices.« less
  • Mapping of the magnetic flux density B{sub z} (perpendicular to the film plane) for a YBa2Cu3O7 thin-film sample was carried out using a scanning micro-Hall probe. The sheet magnetization and sheet current densities were calculated from the B{sub z} distributions. From the known sheet magnetization, the tangential (B{sub x,y}) and normal components of the flux density B were calculated in the vicinity of the film. It was found that the sheet current density was mostly determined by 2B{sub x,y}/d, where d is the film thickness. The evolution of flux penetration as a function of applied field will be shown.
  • The catalytic performance of ceria-based heterogeneous catalysts in many chemical transformations (water-gas shift reaction, CO oxidation, alcohol synthesis from CO/CO{sub 2} hydrogenation, etc.) is affected by the surface structure of the ceria. To control the performance of ceria-containing inverse catalysts, we devised a method to grow ceria nanoparticles (NPs) exposing exclusively either (111) or (100) surfaces and characterized their surface structures by scanning tunneling microscopy. When cerium is vapor-deposited on Cu(111) in a background of molecular O{sub 2}, only CeO{sub 2}(111) NPs grow. However, if the surface of Cu(111) is preoxidized with O{sub 2} or NO{sub 2} to form amore » rectangular copper oxide phase, probably Cu{sub 4}O{sub 3}(001), CeO{sub 2}(100) NPs grow on the oxide template instead. These experimental findings are interpreted using results of density functional calculations. The (100) surface of bulk ceria reconstructs to preserve charge neutrality. This is not necessary for CeO{sub 2}(100) NPs grown on Cu{sub 4}O{sub 3}(001), where the topmost oxygen layer of Cu{sub 4}O{sub 3} is shared with the interfacial layer of cerium. After the CeO{sub 2}(100)/CuO{sub x}/Cu(111) surfaces were exposed to CO, the copper oxide was reduced but the shape of the CeO{sub 2}(100) NPs remained intact. This opens the door for diverse applications in catalysis.« less