The Microstructures and Electrical Resistivity of (Al, Cr, Ti)FeCoNiO_xHigh-Entropy Alloy Oxide Thin Films

Abstract

The (Al, Cr, Ti)FeCoNi alloy thin films were deposited by PVD and using the equimolar targets with same compositions from the concept of high-entropy alloys. The thin films became metal oxide films after annealing at vacuum furnace for a period; and the resistivity of these thin films decreased sharply. After optimum annealing treatment, the lowest resistivity of the FeCoNiOx, CrFeCoNiOx, AlFeCoNiOx, and TiFeCoNiOxfilms was 22, 42, 18, and 35 μΩ-cm, respectively. This value is close to that of most of the metallic alloys. This phenomenon was caused by delaminating of the alloy oxide thin films because the oxidation was from the surfaces of the thin films. The low resistivity of these oxide films was contributed to the nonfully oxidized elements in the bottom layers and also vanishing of the defects during annealing.

Influence of Ti Content on the Partial Oxidation of TixFeCoNi Thin Films in Vacuum Annealing

“…Therefore, Ti migrates to the surface and forms a TiO-rich oxide, the other elements form a FeCoNi-rich alloy which provides a very good conductivity. A similar phenomenon is also observed in AlFeCoNiO x oxide film, because aluminum also has a very high affinity with oxygen [ 2 ]. However, the resistivity of CrFeCoNiO x oxide film is not as low as the oxide films of TiFeCoNiO x and AlFeCoNiO x because of its activity with oxygen.…”

Extremely Polysubstituted Magnetic Material Based on Magnetoplumbite with a Hexagonal Structure: Synthesis, Structure, Properties, Prospects

“…High-entropy oxide nanotubes were also reported [11], but this material is hard to consider as stable crystalline phase. Next, high-entropy phases with a more complex crystal structure-like spinel [12] or (Al,Cr,Ti)FeCoNiO x [13] were achieved. Two papers describe high-entropy phases with the perovskite structure [14,15].…”

“…Some researchers have studied the electrophysical and magnetic properties of high-entropy oxide phases [3,5,6,13,16,17]. It was shown that Ti x FeCoNiO y films have extremely low-electrical resistance values [17].…”

Solid-Phase Synthesis of High-Entropy Crystals with the Magnetoplumbite Structure in the BaO–Fe2O3–TiO2–Al2O3–In2O3–Ga2O3–Cr2O3 System

“…Авторами работы [13] получены тонкие пленки, состав которых соответствует формуле (Al,Cr,Ti)FeCoNiO x . Такие пленки имеют более сложную кристаллическую структуру, чем системы, образованные только оксидами трехвалентных или двухвалентных металлов.…”