Synthesis and characterization of a new high-entropy oxide based on rare-earth elements (Dy,Y,Yb,Nd,Pr)O$_{1.5\pm\delta}$ prepared by citrate–nitrate combustion synthesisSkalar, Tina (Avtor) Levičar, Maks (Avtor) Marinšek, Marjan (Avtor) Genorio, Boštjan (Avtor) Ptáček, Petr (Avtor) Blahut, Jan (Avtor) Sokola, Patrik (Avtor) high-entropy ceramicscombustion synthesisthermal analysisband gapHigh-entropy oxides represent a modern class of materials with broad applicability, in which the configurational entropy of multiple equimolar cations stabilises single-phase structures with unique defect chemistry and tunable functional properties. In the proposed work, a novel rare-earth high-entropy oxide with the composition (Dy,Y,Yb,Nd,Pr)O$_{1.5\pm\delta}$ was synthesized via citrate–nitrate combustion synthesis, followed by calcination in the temperature range 600-1100 °C. Thermogravimetry coupled with mass spectrometry revealed multi-stage decomposition and carbon removal, defining the temperatures required for complete oxidation of carbonaceous residues. High-temperature and ambient XRD analyses confirmed the formation of a single-phase cubic oxide with progressive crystallite growth from ∼10 to 40 nm upon calcination. Optical reflectance measurements showed a semiconducting band gap from 2.26 to 2.39 eV and Urbach energies that reflect changes in structural disorder during calcination. SEM/EDS analyses demonstrated the formation of homogeneous nanocrystals, with surface areas up to 31 m$^2$g$^{−1}$. The study provides a detailed description of phase evolution, defect chemistry, and disorder formation in a combustion-derived rare-earth high-entropy oxide with potential applications in the semiconductor industry.20262026-04-03 11:27:09Članek v reviji181380UDK: 620.1ISSN pri članku: 0272-8842DOI: 10.1016/j.ceramint.2026.03.405COBISS_ID: 274021891sl