Octahedral distortion induced changes in phonon vibration, optical and dielectric properties of xLaAlO3 – (1-x)Ba(Mg1/2 Mo1/2 )O3

Abstract The microstructural, vibrational, optical and impedance spectroscopy of xLaAlO₃–(1-x)Ba(Mg1/2Mo1/2)O₃ [LA-BMM] have been investigated for various values of x. Rhombohedral \(\:R{-}{3}C\:\)(161) phases for LA and cubic \(\:Fm3m\) (225) phases for BMM are revealed by the Refinement of X-ray diffraction (XRD) patterns using Rietveld method for all values of x. XRD patterns demonstrate that the rhombohedral phase systematically increases and the cubic phase systematically decreases with increase of doping concentration x. Several vibrational phonon modes have been identified from the samples room-temperature comparative Raman spectra by group theoretical studies in addition with experimental literature review. Samples band-gaps were gradually decreases from 5.86 eV to 3.96 eV as concentration x increases from 0.10 to 0.90. An LCR meter instrument (Hioki-3532-50, Japan) was used to measure the dielectric data from 300 K to 673 K in the range of frequencies from 50 Hz to 4.8 MHz According to dielectric data, conductivity at room temperature increases when doping concentration x increases.