Characterization of the surface of shock-compacted YB 2C 3O y particles

Abstract

The shock compaction effects on the structural and superconducting properties of high- T c YB 2C 3O y particles are investigated. YB 2C 3O y particles with an average size of 960 nm were prepared by the dry-type jet mill. The lattice constants of the orthorhombic cell with a=0.383 nm, b=0.390 nm and c=1.17 nm for as-shocked YB 2C 3O y particles are calculated just after the shock compaction under 5.71 GPa. In the measurements of susceptibility by SQUID magnetometer, ΔM is obtained. It is found that ΔM(0.00232 emu/g) for as-shocked YB 2C 3O y particles after annealing at 870°C for 10 h is larger than ΔM(0.00047 emu/g) for as-shocked YB 2C 3O y particles, which seems to indicate the new pinning centres created around the grain boundaries during annealing. From scanning electron microscopy observations, the surface of the specimens for as-shocked YB 2C 3O y has large grains of 4–15 μm in length partly with large growth-steps caused mainly by heats generated in shock compaction. Also from the section analysis of atomic force microscope image, the vertical distance of about 30–80 nm is obtained around the edge area in annealed YB 2C 3O y grains.