Low temperature synthesis and characterization of rare earth orthoferrites LnFeO3 (Ln=La, Pr and Nd) from molten NaOH flux

Rare earth orthoferrites of the general formula LnFeO₃ (Ln=La, Pr and Nd) phases have been synthesized for the first time in molten NaOH flux at a temperature as low as 400 ^°C. The flux-grown oxides were characterized by XRD, SEM, EDX, FT-IR and temperature dependent electrical resistivity measurements. The crystal structures of these materials have been refined by the Rietveld profile analysis method using powder XRD data. All these oxides crystallize in the orthorhombic structure (space group Pbnm, no. 62) and exhibit insulating behavior. As-synthesized samples show three active IR absorption bands for Fe-O stretching vibration (ν₁ mode) and O-Fe-O deformation vibration (ν₂ mode). In the KOH flux on the other hand, no product formation is observed, thus providing evidence for the differences in the two alkali fluxes.