Crystal Structure of LaMnO 3+δ Synthesized Using Poly(Acrylic Acid)

Abstract

Poly(acrylic acid) (PAA) was used to make a gel from an aqueous solution of lanthanum and manganese nitrates. In the concentration range 3 × 10 -2 to 5 × 10 -2 M of PAA, the single phase of perovskite-type LaMnO 3+δ was synthesized by firing gels at low temperature. The crystal structure of LaMnO 3+δ changes from hexagonal to orthohombic with increasing concentration of PAA. At 5 × 10 -2 M of PAA, the crystal structure of LaMnO 3+δ changes from orthorhombic to hexagonal with increasing temperature.