Electronic structure property relationship in glassy Ti-Zr-Nb-(Cu,Ni,Co)

Abstract

In this work we revisit vast amount of existing data on physical properties of Ti-Zr-Nb-(Cu,Ni,Co) glassy alloys over a broad range of concentrations (from the high entropy range to that of conventional Cu-, Ni- or Co-rich alloys). By using our new approach based on total content of late transition metal(s), we derive a number of physical parameters of a hypothetical amorphous TiZrNb alloy: lattice parameter $a = (3.42 \pm 0.02)$\r{A}, Sommerfeld coefficient $\gamma = 6.2\,$mJ/mol$\,$K$^2$, density of states at $N(E_F) = 2.6\,(\text{at eV})^{-1}$, magnetic susceptibility $(2.00 \pm 0.05)\,$mJ/T$^2\,$mol, superconducting transition temperature $T_c = (8 \pm 1)\,$K, upper critical field $\mu_0 H_{c2}(0) = (20 \pm 5)\,$T, and coherence length $\xi(0) = (40 \pm 3)\,$\r{A}. We show that our extrapolated results for amorphous TiZrNb alloy would be similar to that of crystalline TiZrNb, except for superconducting properties (most notably the upper critical field $H_{c2}(0)$), which might be attributed to the strong topological disorder of the amorphous phase. Also, we offer an explanation of the discrepancy between the variations of $T_c$ with the average number of valency electrons in neighboring alloys of 4d transition metals and some high entropy alloys. Overall, we find that our novel method of systematic analysis of results is rather general, as it can provide reliable estimates of the properties of any alloy which has not been prepared as yet.