Structural, optical, and dielectric studies of LaFe _1−x Mo _x O ₃ (x = 0.0, 0.5) perovskite materials

The structural, optical, and dielectric properties of LaFe _1−x Mo _x O ₃ (x = 0.0, 0.5) synthesized by the sol–gel method were investigated by X-ray diffraction (XRD), Raman scattering, and impedance spectroscopy. XRD analysis revealed that the x = 0.5 compound is single-phase and orthorhombic, with space group Pbnm, similar to the parent x = 0.0 compound but with larger lattice parameters and/or a larger unit-cell volume. The Raman scattering spectra revealed local lattice distortions in the x = 0.5 compound and spin–phonon coupling related to the magnetic transition (Néel) temperature. The impedance data were well fitted with an R(R ₁ -CPE ₁ )//(R ₂ -CPE ₂ ) equivalent electrical circuit, demonstrating the contributions of both grains and grain boundaries. The temperature (300–500 K) and frequency (100 Hz–1 MHz) dependences of the dielectric properties showed that Mo substitution adversely affected the dielectric parameters.