High magnetic field transport properties of liquid quenched Nb3Al and Nb3Al(Si,Ge) superconducting compounds

Critical current behavior and intrinsic superconducting properties of liquid quenched Nb3Al and its pseudobinaries Nb3 (Al,Si) and Nb3(Al,Ge) have been studied in fields up to 29 T. Our results show that flux pinning in these materials is dominated by strong precipitate pinning at low temperatures and by grain boundary pinning at high (>10 K) temperatures. The best results were obtained in Nb75Al19Ge6 samples with Tc of 20.0 K, estimated Hc2(0) of 43 T and Jc (4.2 K) in excess of 104 A/cm2 at 30 T.