In-Situ Approach to Introduce Flux Pinning in YBCO (Postprint)
Abstract
Several in-situ methods to introduce ultra-high densities of defects into YBCO to enhance flux pinning are reviewed, including rare-earth or chemical substitution or additions, and nanoparticle additions by various processing methods. The results were compiled using studies published recently or that are publicly available. Superconducting and microstructural properties are compared for different nanoparticle additions including Y211, Y2O3, CeO2, Sm123, MgO, La211, IrZO3, BaZrO3, and mixed (Y,RE)123 compositions. Results are included for thin films deposited on single crystals and metallic substrates, and for bulk powders. Of the methods reviewed, only processing conditions that produced nanoparticle additions have demonstrated significant Jc(H) enhancements for high fields Happl>0.3T, whereas rare-earth-only substitutions have increased Jc(H) at low-fields Happl<1T in the case when secondary nanoparticles formations were not observed. For nanoparticle additions high-lattice mismatch materials have given consistently large increase of Jc(H). Results with small-lattice mismatched materials are less consistent thus far; several groups are reporting increases of Jc(H) with large (Y,X)2O3-type nanoparticle size about ~15 nm to ~40 nm, whereas other groups are reporting minimal results with small (Y,X)2O3-type nanoparticle sizes ~5 nm. In this work, very-small lattice mismatches degraded flux pinning presumably by making Y123 more uniform and with less pinning defects.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2012
- Accession Number
- ADA560077
Entities
People
- Timothy J. Haugan
Organizations
- Air Force Research Laboratory