High-field superconductivity in rapidly quenched Ge-M and Al_xO_y-M (M=Pb, Bi, Sn) alloys

Duplex structure alloys consisting of insoluble metallic particles finely and homogeneously embedded in cubic Ge or amorphous Al_xO_y matrix were prepared by a rapid quenching of the insoluble type alloys of Ge-M and Al_xO_y-M (M=Pb, Bi, Sn and In). The duplex alloys were found to exhibit an anomalously high field superconductivity, probably because of the unique dispersed structures which cannot be obtained by the conventional preparation process. The anomalous superconductivity is stated to be a kind of hybrid properties which has so far not been observed for conventional single-phase alloys and composite alloys.