High entropy oxide systems based on rare earth elements

In this paper we synthesized high entropy oxide system (Sc_0.2Ce_0.2Pr_0.2Gd_0.2Ho_0.2)₂O_3±δ by precipitation of hydroxides from REE nitrates aqueous solutions and annealing the mixture at 800 °C. It is possible to obtain the various forms of simple and complex composition based on the rare earth oxides, including oxides in the form of nanosized powders. The main idea of obtaining HEOS comes from the field of high-entropy alloys. The interconnection between configurational entropy and mixing enthalpy is a key factor for determining phase transformations. The phase composition, structure, and surface morphology of the obtained powders were investigated by scanning electron microscopy and X-ray phase analysis methods.