Superconductivity in Metastable BCC Alloys Containing Neptunium

摘要

The possibility of superconductivity in elemental Np has led to a study of superconductivity in bcc solid solutions alloys containing neptunium. Ternary alloys of the form (Np/sub x/U/sub 1-x/)/sub 0.82/Mo/sub 0.18/ and (Np/sub x/U/sub 1-x/)/sub 0.8/Nb/sub 0.2/ were prepared using a rapid quench from the melt. Both the addition of the transition metal and the quench were necessary to retain cubic alloys at room temperature. Superconductivity persisted to x = 0.73 from the Mo alloys and to x = 0.7 for the Nb alloys. At these compositions the loss of superconductivity was apparently due to impurities. Nonetheless, a plot of ln T/sub c/ vs. x yields a straight line from T/sub c/ approximately 2 K for gamma -U(0.18 Mo) or gamma --U(02 Nb) binary alloys at x = 0 to a possible T/subc/ of approximately 30 mK for the same stabilized binary Np alloys at x = 1. (ERA citation 02:020518)