Comments on the paper "Influence of Ba-doping on the structural and physical properties of Sr2-xBaxFeVO6 double perovskites"

We bring attention of the scientific community to erroneous claims about the existence of double per-ovskites "Sr2FeVO6" and "Ba2FeVO6" and their solid solutions in the commented paper. In this commentary, we showed that "Sr2FeVO6" and "Ba2FeVO6" do not exist. We investigated phase formations in such Sr-Fe-V -O and Ba-Fe-V-O compositions in air from 973 K to 1433 K. With our results, we demonstrated that the phase equilibria are reached after annealing at 1173 K, and a mixture of Sr3(VO4)2, cubic perovskite SrFeO3-delta, and SrFe12O19 is formed in case of "Sr2FeVO6", and a mixture of Ba3(VO4)2 and BaFe2O4 is formed in case of "Ba2FeVO6". The mixture of Ba3(VO4)2 and BaFe2O4 is stable up to 1433 K. However, the cubic perovskite SrFeO3-delta in the Sr-Fe-V-O system transforms on further heating at 1273 K and above. The reported magnetic transition temperatures of "Sr2FeVO6" and "Ba2FeVO6" match well with the transition temperatures of SrFe12O19 and BaFe12O19, respectively.(c) 2023 Elsevier B.V. All rights reserved.