Hydrothermal synthesis of perovskite-type BiFeO₃

Abstract

Single crystals of BiFeO₃ were prepared by hydrothermal synthesis using hydrate sodium bismuth oxide (NaBiO₃·nH₂O) and iron nitrates (Fe(NO₃)₃·9H₂O) in the potassium hydroxide solutions. The size of BiFeO₃ single crystals increased with the reaction temperature and duration. Single crystals of sillenite-type Bi_12.5Fe_0.5O_19.5 and Bi₂Fe₄O₉ were also obtained depending on the conditions. From the chemical analysis, the chemical composition of the crystals was deduced to be Bi_0.96K_0.03FeO₃. Although the crystals contained a small amount of potassium, the lattice parameters of the crystals agreed well with the pure BiFeO₃ and the Curie temperature was not affected by this replacement.