New High-Entropy Oxide Phases with the Perovskite Structure

In the studied BaO–SrO–CaO–La2O3–Fe2O3–TiO2–Al2O3–Mn2O3–CoO–In2O3–Ga2O3–Cr2O3 system there were synthesized three new high-entropy magnetoplumbite phases by solid-state sintering in air at 1300, 1350, and 1400 °C. The average composition of the high-entropy phases obtained at 1350 °C can be described by the formulas: Ba 0.48 Sr 0.30 Ca 0.05 La 0.15 Fe 1.62 Ti 1.78 Al 1.55 Mn 1.45 Co 1.11 In 1.29 Ga 1.52 Cr 1.71 O 19 ; Ba 0.39 Sr 0.37 Ca 0.05 La 0.18 Fe 2.88 Ti 1.60 Al 1.69 Mn 1.09 Co 0.92 In 1.20 Ga 1.27 Cr 1.38 O 19 ; Ba 0.37 Sr 0.29 Ca 0.05 La 0.28 Fe 5.85 Ti 1.15 Al 0.97 Mn 0.74 Co 0.56 In 0.85 Ga 0.94 Cr 0.97 O 19 . The data obtained indicate that a significant portion of calcium was not incorporated into the high-entropy phase. This must be taken into account in the course of subsequent experimental work on the creation of homogeneous phases necessary for the study of their electrical and magnetic properties.