Enhanced superconductivity in Hf-base metallic glasses

A systematic study of electrical resistivity of Hf100-xFex (x 20,25), Hf100-xCux(x = 30,40,50) and Ti65Cu35 metallic glasses has been done in the temperature range 0.3-290 K, and in magnetic fields B≤5 T. All Hf-base alloys are superconducting with Tc≥0.44 K, which is well above the Tc of pure crystalline Hf (0.13 K). From the initial slopes of the upper critical fields, (dHc2/dT)Tc, and resistivities we determined the dressed electronic densities of states, Nγ(EF), for all alloys. Both Tc and Nγ(EF) decrease with increasing x (Fe and Cu content). The results are compared with those for corresponding Zr-base metallic glasses and ion-implanted Hf films.