2023/11/01 by Takeru Seki, Seki, Takeru, Hiroto Arima +9 · 1 citation
Engineering · #Advanced Materials Characterization Techniques #High Entropy Alloys Studies #Intermetallics and Advanced Alloy Properties
paper · pdf · doi:10.48550/arxiv.2311.00195
We investigated the impact of annealing on the structural characteristics and superconducting critical temperature (Tc) of the eutectic high-entropy alloy (HEA) superconductor NbScTiZr. The HEA manifests an eutectic microstructure composed of body-centered cubic (bcc) and hexagonal close-packed phases. Both the lattice parameters of the bcc phase and grain size of the eutectic structure exhibited pronounced sensitivity to variations in annealing temperature. The observed dependence of the lattice parameter on annealing temperature supports the possibility that lattice strain occurs at lower annealing temperatures. The as-cast sample demonstrated superconductivity at Tc of 7.9 K, which increased to 9 K after annealing at 800 ∘C. However, when subjected to annealing at 1000 ∘C, Tc diminishes to 8.7 K. The annealing-temperature dependence of Tc cannot be comprehensively elucidated based solely on the electronic density of states at the Fermi level. It is plausible that the lattice strain may influence the annealing temperature dependence of Tc. Our results for the critical current density Jc reveal that the self-field Jc of the as-cast NbScTiZr at 2 K exceeds 106 A/cm2.