The Low Electrical Resistivity of the High-entropy Alloy Oxide Thin Films

This paper reports the new compositions of oxide thin films with very low electrical resistivity. We have found that some of the high-entropy alloy oxide thin films which still had very low electrical resistivity. In this study, we deposited the thin films of TixFeCoNi (x=0, 0.25, 0.5, 0.75 and 1), TiFeCoNiCux (x=1, 2 and 3), and AlxCrFeCoNiCu (x=0.5 and 1) by PVD, all the targets were prepared by arc-melting under Ar atmosphere. The microstructures of the specimens were examined by SEM and TEM; the electrical resistivities of the specimens were measured by four point probe equipment. Results indicated the microstructures of the as-deposited alloy thin films were amorphous. All of the thin films were oxidized and became to semiconductors after annealed by vacuum furnace, also their microstructures transformed to nanocrystalline FCC microstructures. The electrical resistivities of these high entropy alloy oxides were about 30 μΩ-cm for the TixFeCoNi oxide thin films, about 100 μΩ-cm for the TiFeCoNiCu3 oxide thin film and about 650 μΩ-cm for the Al0.5CrFeCoNiCu oxide thin film. That is, we found the new compositions of oxides with very low electrical resistivity. This is the most important result of this study, and it could also be very important contribution to the electrical ceramics.