Papers by Author: Yin Bo Wang

Abstract: We have fabricated MgB2 thick films on SiC substrates growing along c axis by using hybrid physical–chemical vapor deposition (HPCVD) technique. The thickness was 8μm. Electric measurement showed that the Tc (onset) was 41.4K, and the transition width was 0.5K, the residual resistance ratio (RRR) was near 7. Magnetic measurement showed that the critical current density was 1.7×106A/cm2 at 5K in a self field.

Abstract: We have fabricated several superconducting MgB₂ thin films on stainless steel substrates by using hybrid physical-chemical vapor deposition (HPCVD) in pure argon atmosphere. These films were observed by scanning electron microscopes (SEM) and used the energy dispersive X-ray spectroscopy (EDX) to make elements analyses. The film thickness is about 800~1000 nm. There were some cracks on the film surface when the film is bent by different angle. The number of cracks and their width increased with the increasing bending angle. Nevertheless, the films were attached to the substrates firmly. It concludes that the superconducting MgB₂ thin films have great ductility and adhesion to the stainless steel substrates. We found in these films many granules about tens of nanometers in size. These nano-granules can balance both the inner structure and the surface activity of the MgB₂ crystal. This might be an important reason for the ductility observed with the superconducting thin films. The exact explanation depends on further research.