We report the magneto-optical imaging for polycrystalline LaFeAsO 0.95F0.05 and LaFeAsO0.892F0.108. We find a significant magneto-optical contrast with marked inhomogeneities and with a typical superconducting grain size ∼20-40 μm. Although intergrain critical current density is negligibly small, intragrain critical current density obtained from magneto-optical image is about 1 × 105 A/cm2 at 5 K, which is smaller than other rare-earth-based iron-oxypnictide superconductors but is potentially attractive for technological applications.
- Critical current density
- Magneto-optical imaging
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering