Resumen de Effect of Re and Tm-site on morphology structure and optical band gap of ReTmO_(3) (Re = La, Ce Nd, Gd, Dy, Y and Tm = Fe, Cr) prepared by sol-gel method
M. Tufiq Jamil, J. Ahmad, S. Hamad Bukhari, M. Saleem
Rare earth nano sized pollycrystalline orthoferrites and orthocromites ReTmO_(3) (Re = La, Nd, Gd, Dy, Y and Tm = Fe, Cr) have been synthesized by sol-gel auto combustion citrate method. The samples have been characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and UV-visible spectroscopy. The samples are single phase, as confirmed by XRD analysis, and correspond to the orthorhombic crystal symmetry with space group pbnm. Debye Scherer formula and Williamson Hall analysis have been used to calculate the average grain size, which is consistent with that of determined from SEM analysis and varied between 25-75 nm. The elemental compositions of all samples have been checked by EDX analysis. Different crystallographic parameters are calculated with strong structural correlation among Re and Tm sites. The optical energy band gap has been calculated by using Tauc relation estimated to be in the range of 1.77 - 1.87 eV and 2.77 - 3.14 eV, for ReFeO_(3) and ReCrO_(3), respectively.
