skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • The benefit of Ca in improving pinning of BaZrO 3 -Y 2 O 3 doubly-doped YBa 2 Cu 3 O 7-x /Ca 0.3 Y 0.7 Ba 2 Cu 3 O 7-x multilayer nanocomposite films
Title: The benefit of Ca in improving pinning of BaZrO 3 -Y 2 O 3 doubly-doped YBa 2 Cu 3 O 7-x /Ca 0.3 Y 0.7 Ba 2 Cu 3 O 7-x multilayer nanocomposite films
Abstract This work examines the pinning enhancement in BaZrO 3 (BZO) +Y 2 O 3 doubly-doped (DD) YBa 2 Cu 3 O 7 (YBCO) nanocomposite multilayer (DD-ML) films. The film consists of two 10 nm thin Ca 0.3 Y 0.7 Ba 2 Cu 3 O 7-x (CaY-123) spacers stacking alternatively with three BZO + Y 2 O 3 /YBCO layers of 50 nm each in thickness that contain 3 vol% of Y 2 O 3 and BZO doping in the range of 2–6 vol%. Enhanced magnetic vortex pinning and improved pinning isotropy with respect to the orientation of magnetic field (B) have been achieved in the DD-ML samples at lower BZO doping as compared to that in the single-layer counterparts (DD-SL) without the CaY-123 spacers. For example, the pinning force density ( F p ) of ∼58 GNm −3 in 2 vol.% of DD-ML film is ∼110% higher than in 2 vol% of DD-SL at 65 K and B // c -axis, which is attributed to the improved pinning efficiency by c -axis aligned BZO nanorods through diffusion of Calcium (Ca) along the tensile-strained channels at BZO nanorods/YBCO interface for improvement of the interface microstructure and hence pinning efficiency of BZO nanorods. An additional benefit is in the considerably improved J c ( θ ) and reduced J c anisotropy in the former over the entire range of the B orientations. However, at higher BZO doping, the BZO nanorods become segmented and misoriented, which may change the Ca diffusion pathways and reduce the benefit of Ca in improving the pinning efficiency of BZO nanorods.  more » « less
Award ID(s):
1909292
PAR ID:
10409057
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Materials Research Express
Volume:
10
Issue:
4
ISSN:
2053-1591
Page Range / eLocation ID:
046001
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; ; (, Superconductor Science and Technology)
    Abstract One-dimensional c -axis-aligned BaZrO 3 (BZO) nanorods are regarded as strong one-dimensional artificial pinning centers (1D-APCs) in BZO-doped YaBa 2 Cu 3 O 7− x (BZO/YBCO) nanocomposite films. However, a microstructure analysis has revealed a defective, oxygen-deficient YBCO column around the BZO 1D-APCs due to the large lattice mismatch of ∼7.7% between the BZO (3a = 1.26 nm) and YBCO (c = 1.17 nm), which has been blamed for the reduced pinning efficiency of BZO 1D-APCs. Herein, we report a dynamic lattice enlargement approach on the tensile strained YBCO lattice during the BZO 1D-APCs growth to induce c -axis elongation of the YBCO lattice up to 1.26 nm near the BZO 1D-APC/YBCO interface via Ca/Cu substitution on single Cu-O planes of YBCO, which prevents the interfacial defect formation by reducing the BZO/YBCO lattice mismatch to ∼1.4%. Specifically, this is achieved by inserting thin Ca 0.3 Y 0.7 Ba 2 Cu 3 O 7− x (CaY-123) spacers as the Ca reservoir in 2–6 vol.% BZO/YBCO nanocomposite multilayer (ML) films. A defect-free, coherent BZO 1D-APC/YBCO interface is confirmed in transmission electron microscopy and elemental distribution analyses. Excitingly, up to five-fold enhancement of J c ( B ) at magnetic field B = 9.0 T// c -axis and 65 K–77 K was obtained in the ML samples as compared to their BZO/YBCO single-layer (SL) counterpart’s. This has led to a record high pinning force density F p together with significantly enhanced B max at which F p reaches its maximum value F p,max for BZO 1D-APCs at B // c -axis. At 65 K, the F p,max ∼158 GN m −3 and B max ∼ 8.0 T for the 6% BZO/YBCO ML samples represent a significant enhancement over F p,max ∼ 36.1 GN m −3 and B max ∼ 5.0 T for the 6% BZO/YBCO SL counterparts. This result not only illustrates the critical importance of a coherent BZO 1D-APC/YBCO interface in the pinning efficiency, but also provides a facile scheme to achieve such an interface to restore the pristine pinning efficiency of the BZO 1D-APCs. 
    more » « less
  2. ; ; ; ; ; ; (, IOP Conference Series: Materials Science and Engineering)
    Abstract C-axis aligned BaZrO3(BZO) nanorods formed via strain-mediated self-assembly in BZO-doped YaBa2Cu3O7-x(BZO/YBCO) nanocomposite films can provide strong pinning to the quantized magnetic vortices. While the strain initiated from the BZO/YBCO lattice mismatch plays a critical role in nucleation and evolution of the BZO nanorods, it also leads to a highly defective BZO/YBCO interface and hence reduced pinning efficiency of BZO nanorods. This work reports a recent study in probing the effect of BZO/YBCO interface on the pinning efficiency of the BZO nanorods as the interface is repaired dynamically during the BZO nanorod growth using Ca doping. Within the BZO doping range of 2-8 vol.%, significantly enhanced pinning efficiency of the BZO nanorods have been observed. A peak enhancement up to five-fold of critical current density at 9.0 T and 65-77 K has been obtained in the 6 vol.% BZO/YBCO nanocomposites after the interface repair. This result not only illustrates the critical importance of the BZO/YBCO interface in the pinning efficiency, but also provides a facile scheme to achieve such an interface to restore the pristine pinning efficiency of the BZO nanorods. 
    more » « less
  3. ; ; ; ; ; ; ; ; ; (, Superconductor Science and Technology)
    Abstract BaZrO3(BZO) one-dimensional artificial pinning centers (1D-APCs) aligned along thec-axis of the YBa2Cu3O7(YBCO) have been adopted to enhance the magnetic vortex pinning in BZO/YBCO nanocomposite films. However, the pinning force densityFpof the BZO 1D-APCs remains moderate at temperatures near 77 K. A hypothesis of the major limiting factor is the defective BZO 1D-APCs/YBCO interface as a direct consequence of the large interfacial strain originated from the BZO/YBCO lattice mismatch of ∼7.7%. Herein, we explore enlarging thec-axis of the YBCO dynamically to reduce the lattice mismatch and hence to prevent formation of the defective BZO 1D-APCs/YBCO interface. Specifically, thec-axis enlargement was achieved by partial replacement of Cu with Ca on the YBCO lattice using strain-directed Ca diffusion into YBCO from two Ca0.3Y0.7Ba2Cu3O7−x(CaY-123) spacers of only 10 nm in thickness inserted into the 2 vol% BZO 1D-APC/YBCO nanocomposite thin films of ∼150 nm in total thickness. The achieved elongatedc-axis is attributed to the formation of stacking faults induced by Ca-replacement of Cu on YBCO lattice. The reduced BZO/YBCO lattice mismatch allows formation of a coherent BZO 1D-APC/YBCO interface with negligible defects. This leads to an enhancedFpvalue up to 98 GN m−3at 65 K, which is 70% higher than that of the reference 2 vol% BZO 1D-APC/YBCO sample. Furthermore, the benefit of the enhanced pinning of the BZO 1D-APCs with a coherent interface with YBCO can be extended to a large angular range of the magnetic field orientation. This study reveals the significant effect of the BZO/YBCO interface on the pinning efficiency of BZO 1D-APCs and provides a promising approach to achieve a coherent interface in BZO/YBCO nanocomposite films. 
    more » « less
  4. ; ; ; ; ; ; ; ; ; ; et al (, IOP Conference Series: Materials Science and Engineering)
    Abstract The BaZrO 3 /YBa 2 Cu 3 O 7 (BZO/YBCO) interface has been found to affect the vortex pinning efficiency of one-dimensional artificial pinning centers (1D-APC) of BZO. A defective BZO/YBCO interface due to a lattice mismatch of ∼7.7% has been blamed for the reduced pinning efficiency. Recently, we have shown incorporating Ca 0.3 Y 0.7 Ba 2 Cu 3 O 7-x spacer layers in BZO/YBCO nanocomposite film in multilayer (ML) format can lead to a reduced lattice mismatch ∼1.4% through the enlargement of lattice constant of YBCO via Ca diffusion and partial Ca/Cu replacement on Cu-O planes. In this work, the effect of this interface engineering on the BZO 1D-APC pinning efficiency is investigated at temperatures of 65-81 K through a comparison between 2 and 6 vol.% BZO/YBCO ML samples with their single-layer (SL) counterparts. An overall higher pinning force ( F p ) density has been observed on the ML samples as compared to their SL counterparts. Specifically, the peak value of F p ( F p,max ) for the 6% BZO/YBCO ML film is about ∼ 4 times of that of its SL counterpart at 65 K. In addition, the location of the F p,max ( B max ) in the ML samples shifts to higher values as a consequence of enhanced pinning. For the 6% BZO/YBCO ML sample, a much smaller “plateau-like” decrease of the B max with increasing temperature was observed, which is in contrast to approximately linear decrease of B max with increasing temperature in the 6% SL film. This result indicates the importance of restoring the BZO/YBCO interface quality for better pinning efficiency of BZO 1D-APCs especially at higher BZO doping concentration. 
    more » « less
  5. ; ; ; ; ; ; ; ; ; (, Journal of Applied Physics)
    High critical current (Ic) in high magnetic fields (B) with minimal variations with respect to the orientation of the B field is demanded by many applications such as high-field magnets for fusion systems. Motivated by this, this work studies 6 vol. % BaZrO3/YBa2Cu3O7 (BZO/YBCO) multilayer nanocomposite films by stacking two 10 nm thick Ca0.3Y0.7Ba2Cu3O7 (CaY-123) spacers with three BZO/YBCO layers of thickness varied from 50 to 330 nm to make the total film thickness of 150–1000 nm. The Ca diffusion from the spacers into BZO/YBCO was shown to dramatically enhance pinning efficiency of c-axis aligned BZO nanorods, which yields high and almost thickness independent critical current density (Jc) in the BZO/YBCO multilayer nanocomposite films. Remarkably, enhanced Jc was observed in these multilayer samples at a wide temperature range of 20–80 K and magnetic fields up to 9.0 T. In particular, the thicker BZO/YBCO multilayer films outperform their thinner counterparts in both higher value and less anisotropy of Jc at lower temperatures and higher fields. At 20 K and 9.0 T, Ic is up to 654 A/cm-width at B//c in the 6% multilayer (1000 nm) sample, which is close to 753 A/cm-width at B//ab due to the intrinsic pinning. This result illustrates the critical role of the Ca cation diffusion into the YBCO lattice in achieving high and isotropic pinning in thick BZO/YBCO multilayer films. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email