The investigation of structural and vibrational properties and optical behavior of Ti-doped La0.67Ba0.25Ca0.08Mn(1-x)TixO3 (x=0.00, 0.05 and 0.10) manganites

The influence of Ti4+ ions incorporated into the B site on the structural, vibrational and optical properties of La0.67Ba0.25Ca0.08Mn(1-x)TixO3 (LBCM(1-x)Tx), a polycrystalline compound prepared by a molten salt method, was discussed. The X-ray diffraction (XRD) studies confirmed that at room temperature these compounds crystallize in the rhombohedral phases of R3c. Rietveld refinement indicated that the octahedron (Mn/Ti)O-6 underwent a slight deformation and the theta((Mn/Ti)-O-(Mn/Ti)) bond angles decreased with the increase in the Ti content. Furthermore, Raman spectra were recorded at room temperature for the LBCM(1-x)Tx ceramics to investigate the influence of incorporated Ti4+ ions in LBCM(1-x)Tx. Moreover, we controlled the frequency and damping of the optic modes based on Ti incorporation. The infrared (IR) absorption spectrum (FTIR) analysis in the span of 420-750 cm(-1) supports the XRD results. The diffuse reflectance data at room temperature verified that both transition levels (E-5(g) -> T-5(5g)) and ((4)A(2g) -> T-4(2g)) correspond to the Mn3+ and Mn4+ ions. The optical band gap (E-g) values decreased from 2.90 eV to 2.70 eV with the increase in the Ti4+ content, implying that our samples could be good candidates for some applications in luminescent devices, such as ultrafast optoelectronic devices. Moreover, the photoluminescence spectra (PL) features at room temperature decreased for all samples. CIE were estimated for all the concentrations of Ti4+ ions. The results indicated that are a shifts in the CIE values of the compounds.