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Title: Strong Enhancement of Flux Pinning in YBa 2Cu 3O 7-δ Multilayers with Columnar Defects Comprised of Self-Assembled BaZrO 3

Abstract

Multilayer structures comprising YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films with columns of self-assembled BaZrO{sub 3} (BZO) nanodots with interlayers of CeO{sub 2} or pure YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} were grown on rolling-assisted biaxially textured substrates (RABiTSs) using pulsed laser deposition. A significant enhancement of the critical current density (J{sub c}) was observed for the multilayers compared with a single layer of YBCO + BZO. J{sub c} varies as J{sub c}{approx}H{sup -{alpha}} with a of 0.27 for single layer of YBCO + BZO and 0.34 for both multilayered films. Enhancement of pinning in the multilayers is attributed to the presence of columnar defects comprised of self-assembled nanodots of BZO as well as planar CuO-type stacking defects arising as a result of interfacial reactions in the multilayers.

Authors:
 [1];  [1];  [1];  [1];  [1]
  1. ORNL
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:
931336
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Superconductor Science & Technology; Journal Volume: 20
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; CRITICAL CURRENT; CRYSTAL DEFECTS; MAGNETIC FLUX; YTTRIUM OXIDES; BARIUM OXIDES; COPPER OXIDES; FILMS; QUANTUM DOTS; ZIRCONIUM OXIDES; CERIUM OXIDES; CURRENT DENSITY

Citation Formats

Kang, Sukill, Leonard, Keith J, Martin, Patrick M, Li, Jing, and Goyal, Amit. Strong Enhancement of Flux Pinning in YBa2Cu3O7-δ Multilayers with Columnar Defects Comprised of Self-Assembled BaZrO3. United States: N. p., 2007. Web. doi:10.1088/0953-2048/20/1/003.
Kang, Sukill, Leonard, Keith J, Martin, Patrick M, Li, Jing, & Goyal, Amit. Strong Enhancement of Flux Pinning in YBa2Cu3O7-δ Multilayers with Columnar Defects Comprised of Self-Assembled BaZrO3. United States. doi:10.1088/0953-2048/20/1/003.
Kang, Sukill, Leonard, Keith J, Martin, Patrick M, Li, Jing, and Goyal, Amit. Mon . "Strong Enhancement of Flux Pinning in YBa2Cu3O7-δ Multilayers with Columnar Defects Comprised of Self-Assembled BaZrO3". United States. doi:10.1088/0953-2048/20/1/003.
@article{osti_931336,
title = {Strong Enhancement of Flux Pinning in YBa2Cu3O7-δ Multilayers with Columnar Defects Comprised of Self-Assembled BaZrO3},
author = {Kang, Sukill and Leonard, Keith J and Martin, Patrick M and Li, Jing and Goyal, Amit},
abstractNote = {Multilayer structures comprising YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films with columns of self-assembled BaZrO{sub 3} (BZO) nanodots with interlayers of CeO{sub 2} or pure YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} were grown on rolling-assisted biaxially textured substrates (RABiTSs) using pulsed laser deposition. A significant enhancement of the critical current density (J{sub c}) was observed for the multilayers compared with a single layer of YBCO + BZO. J{sub c} varies as J{sub c}{approx}H{sup -{alpha}} with a of 0.27 for single layer of YBCO + BZO and 0.34 for both multilayered films. Enhancement of pinning in the multilayers is attributed to the presence of columnar defects comprised of self-assembled nanodots of BZO as well as planar CuO-type stacking defects arising as a result of interfacial reactions in the multilayers.},
doi = {10.1088/0953-2048/20/1/003},
journal = {Superconductor Science & Technology},
number = ,
volume = 20,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • We report significant enhancement in the flux-pinning of epitaxial NdBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (NdBCO) films on rolling-assisted biaxially textured substrates (RABiTS) via the incorporation of a two-dimensional array of columnar defects comprised of self-assembled BaZrO3 (BZO) nanodots. Pure NdBCO films and NdBCO films incorporating BZO nanodots, both with the same thickness of 0.6 {micro}m, were epitaxially grown on RABiTS by pulsed laser deposition. A very dense and homogeneous distribution of BZO nanodot columns with typical intercolumn spacing of around 15-20 nm oriented along the c-axis of the film was observed in the NdBCO+BZO film. Compared to the pure NBCO filmmore » on RABiTS, the NdBCO+BZO film on RABiTS has an in-field critical current density (J{sub c}) of a factor of more than 2 in 0.1-1.5 T and a smaller power-law exponent {alpha}{approx}0.21 in the field regime where J{sub c}{approx}H{sup -{alpha}}.« less
  • The development of biaxially textured, second-generation, high-temperature superconducting (HTS) wires is expected to enable most large-scale applications of HTS materials, in particular electric-power applications. For many potential applications, high critical currents in applied magnetic fields are required. It is well known that columnar defects generated by irradiating high-temperature superconducting materials with heavy ions significantly enhance the in-field critical current density. Hence, for over a decade scientists world-wide have sought means to produce such columnar defects in HTS materials without the expense and complexity of ionizing radiation. Using a simple and practically scalable technique, we have succeeded in producing long, nearlymore » continuous vortex pins along the c-axis in YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO), in the form of self-assembled stacks of BaZrO{sub 3} (BZO) nanodots and nanorods. The nanodots and nanorods have a diameter of {approx}2-3 nm and an areal density ('matching field') of 8-10 T for 2 vol.% incorporation of BaZrO{sub 3}. In addition, four misfit dislocations around each nanodot or nanorod are aligned and act as extended columnar defects. YBCO films with such defects exhibit significantly enhanced pinning with less sensitivity to magnetic fields H. In particular, at intermediate field values, the current density, J{sub c}, varies as J{sub c} {approx}H{sup -{alpha}}, with {alpha} {approx} 0.3 rather than the usual values 0.5-0.65. Similar results were also obtained for CaZrO{sub 3} (CZO) and YSZ incorporation in the form of nanodots and nanorods within YBCO, indicating the broad applicability of the developed process. The process could also be used to incorporate self-assembled nanodots and nanorods within matrices of other materials for different applications, such as magnetic materials.« less
  • Thick, epitaxial NdBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (NdBCO) films (up to 2.1 {micro}m) with a high density of nanoscale columnar defects parallel to the c-axis of the film were deposited on ion-beam assisted deposition-MgO templates via pulsed laser deposition. The columnar defects were composed of self-assembled BaZrO{sub 3} (BZO) nanodots. A significant enhancement in J{sub c} for H||c is found for these films. In addition, an overall improvement in the in-field J{sub c} at all field orientations is observed. Compared to pure NdBCO of similar thickness, the in-field Jc at H||c for 0.7 {micro}m thick NdBCO+BZO film is improved by amore » factor of 2-4 in the field range of 0.1-4 T and 10-20 at 7-8 T at 77 K. In addition, a smaller {alpha}{approx}0.17 is found in the field regime where J{sub c}{approx}H{sup -{alpha}}. Also, a higher maximum pinning force, F{sub p}{sup max}{approx}14 GN/m3, is found at 3 T and a larger H{sub irr} over 8 T is found for the NdBCO films with columnar defects.« less