Enabling coherent BaZrO3nanorods/YBa2Cu3O7−xinterface through dynamic lattice enlargement in vertical epitaxy of BaZrO3/YBa2Cu3O7−xnanocomposites
Abstract
One-dimensionalc-axis-aligned BaZrO3(BZO) nanorods are regarded as strong one-dimensional artificial pinning centers (1D-APCs) in BZO-doped YaBa2Cu3O7−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 inducec-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 Ca0.3Y0.7Ba2Cu3O7−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 ofJc(B) at magnetic fieldB= 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 densityFptogether with significantly enhancedBmaxat whichFpreaches its maximum valueFp,maxfor BZO 1D-APCs atB//c-axis. At 65 K, theFp,max∼158 GN m−3andBmax∼ 8.0 T for the 6% BZO/YBCO ML samples represent a significant enhancement overFp,max∼ 36.1 GN m−3andBmax∼ 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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 04, 2022
- Source ID
- 10.1088/1361-6668/ac4aff
Entities
People
- Bibek Gautam
- Di Zhang
- Haiyan Wang
- Jie Jian
- Jijie Huang
- Judy Z Wu
- Mary Ann Sebastian
- Timothy J. Haugan
- Victor Ogunjimi
- Yifan Zhang
Organizations
- Air Force Office of Scientific Research
- National Science Foundation