LAUSR

The detailed study of the solid solutions with the general composition La1 − xBixMn1 − yFeyO3 + δ (x = 0.1–0.3, y = 0.1–0.3) prepared by means of solid-phase synthesis has been performed for the first time. The synthesized samples crystallize in an R-centered trigonal unit cell at room temperature and have the oxygen nonstoichiometry index δ = 0.15. The existence of two types of crystallites with related but yet different space groups has been established for La0.7Bi0.3Mn0.9Fe0.1O3 + δ by high-resolution transmission electron microscopy. All the samples experience chemical expansion at temperatures above 650°C. The thermal expansion coefficient is 11.6 × 10−6°C−1 in the low-temperature region (25–650°C) and 12.3 × 10−6°C−1 in the high-temperature region (650–1000°C). The electroconductivity of all the studied solid solutions in the temperature range 800–200°C is slightly lower than for undoped lanthanum manganite.