Enabling coherent BaZrO3 nanorods/YBa2Cu3O7−x interface through dynamic lattice enlargement in vertical epitaxy of BaZrO3/YBa2Cu3O7−x nanocomposites. (4th February 2022)

• Record Type: Journal Article
• Authors: Wu, Judy Z; Ogunjimi, Victor; Sebastian, Mary Ann; Zhang, Di; Jian, Jie; Huang, Jijie; Zhang, Yifan; Gautam, Bibek; Haugan, Timothy; Wang, Haiyan
• Is Part Of: Superconductor science & technology. Volume 35:Number 3(2022)
• Publication Date: 2022-02-04
• Subjects: YBCO nanocomposites -- 1D artificial pinning center -- vortex pinning efficiency -- vertical epitaxy -- coherent interface -- dynamic lattice enlargement; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/ac4aff
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: One-dimensional c -axis-aligned BaZrO3 (BZO) nanorods are regarded as strong one-dimensional artificial pinning centers (1D-APCs) in BZO-doped YaBa2 Cu3 O7− 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 Ca0.3 Y0.7 Ba2 Cu3 O7− 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.