Superconductivity of rapidly quenched YC(NiB)x (x=2,3,4) borocarbides

We have carried out superconductivity measurements of rapid-quenched YC(NiB)x (x = 2,3,4) borocarbides. To obtain the rapid-quenched materials, both splat-cooling as well as melt-spinning techniques have been used. Melt spinning was performed in pure Ar on a copper wheel with a peripheral speed of about 40 m/s with 6 x 10-5 Torr vacuum. Splat quenching was performed in an arc melter with a copper rod impinging at a blow on a small droplet of the molten sample. The critical temperature as high as 16 K is found in the rapid quenched YNi3B3C ribbon sample. Our results show that this class of superconductors made by the rapid-quenched method has an obvious advantage with a direct processing into ribbon which are more useful for applications. (orig.)