Additional Flux Pinning in Sn-Doped Nb3Al Superconductor

The Nb 3 (Al 1− x Sn x ) superconductor with enhanced critical current density ( J c ) is prepared by the process of mechanical alloying (MA) and subsequent low-temperature sintering and the enhancement mechanism of J c in Nb 3 (Al 1− x Sn x ) is discussed. The analysis of the flux pinning force implies that there is an additional pinning mechanism apart from grain boundary pinning in Nb 3 (Al 1− x Sn x ). The existence of dispersed Nb 2 Al nanoparticles (<30 nm) in Nb 3 (Al 1− x Sn x ) is confirmed by microstructure observation. These nanosized Nb 2 Al particles can serve as flux pinning centers, which leads to the increase of the flux pinning force as well as the enhancement of Nb 3 (Al 1− x Sn x )'s J c performance.