Superconducting property of Zr-Co and Zr-Co-Al alloys fabricated by rapid solidification

The superconducting property of Zr _{(1 x)} Co _x (x = 10-50 at.%) alloys and a Zr ₅₅ Co ₃₀ Al ₁₅ bulk metallic glass fabricated using techniques of rapid solidification was investigated. The Zr ₅₅ Co ₃₀ Al ₁₅ alloy crystallized by heat treatment in a vacuum atmosphere exhibited superconductivity of T _c,on = 2.4 K. This was attributable to the superconducting property of a crystalline Zr-Co alloy precipitated in the Zr ₅₅ Co ₃₀ Al ₁₅ alloy. The T _c,on of the crystalline Zr _{(1 x)} Co _x alloy was sensitive to the Co content. The increase of Co content for the Zr _{(1 x)} Co _x alloy led to the decrease of T _c,on . The Zr _{(1 x)} Co _x alloy exhibited superconductivity of a maximum T _c,on = 3.9 K for the Zr ₈₀ Co ₂₀ alloy with superconducting nanocrystal particles embedded in the amorphous matrix.