Molecular Dynamics Simulation of Structural and Transport Properties of Solid Solutions of Double Perovskites Based on PrBaCo₂O_5.5

The oxygen diffusion has been simulated by the molecular dynamics method in the solid solutions of PrBaCo₂O_5.5-based double perovskites: PrBa_0.5Sr_0.5Co₂O_5.5 with random substitution of half of Ba atoms by Sr atoms, PrBa_0.5Sr_0.5CoFeO_5.5 with random substitution Ba → Sr and Co → Fe, PrBa_0.5Sr_0.5CoCuO_5.5 with random substitution Ba → Sr and Co → Cu, and PrBa_0.5Sr_0.5CuFeO_5.5 with random substitution Ba → Sr and random substitution of Co atoms by Fe and Cu atoms. It is shown that, varying the oxygen nonstoichiometry and/or chemical composition of solid solutions based on PrBa_0.5Sr_0.5Co₂O_5.5, one can significantly change the coefficient of thermal expansion of the materials. It is established for the first time that the maximum difference between the mobilities of oxygen atoms of different types observed in PrBa_0.5Sr_0.5Co₂O_5.5 significantly decreases at partial substitutions of cobalt by iron and copper. In the PrBa_0.5Sr_0.5CuFeO_5.5 solid solution, the oxygen atom mobility in the (Cu,Fe)–O layers becomes somewhat higher than that in the Pr–O layers.