Enhanced superconductivity in Hf-base metallic glasses

TL;DR

This study investigates superconductivity in Hf-based metallic glasses, revealing enhanced T_c compared to pure Hf and analyzing how composition affects electronic properties and superconducting behavior.

Contribution

It provides the first systematic analysis of superconductivity in Hf-based metallic glasses and links composition to electronic density of states and critical temperature.

Findings

Hf-based alloys are superconducting with T_c >= 0.44 K.

T_c and electronic density of states decrease with increasing Fe and Cu content.

Comparison with Zr-based glasses and Hf films highlights compositional effects.

Abstract

Systematic study of electrical resistivity of Hf_{100-x}Fe_x (x=20,25), Hf_{100-x}Cu_x (x=30,40,50), and Ti_{65}Cu_{35} metallic glasses has been done in the temperature range 0.3 K - 290 K, and in magnetic fields B <= 5 T. All Hf-base alloys are superconducting with T_c >= 0.44 K, which is well above T_c of pure crystalline Hf (0.13 K). From the initial slopes of the upper critical fields, (dH_{c2}/dT)_{T_c}, and resistivities we determined the dressed electronic densities of states, N_{\gamma}(E_F), for all alloys. Both T_c and N_{\gamma}(E_F) 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.