Effect of Re and Tm-site on morphology structure and optical band gap of ReTmO3 (Re: La, Ce, Nd, Gd, Dy, Y and Tm: Fe, Cr) prepared by sol-gel method

Abstract

Rare earth nano sized pollycrystalline orthoferrites and orthocromites ReT mO3 (Re = La, Nd, Gd, Dy, Y and T m = 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 ReFeO3 and ReCrO3, respectively.

Modeling of the oxygen defect formation in YCrO3

“…The determined band gap for the perovskite was found to be 1.64 eV. In the literature, the reported band gap values for different forms of yttrium chromite (crystal, thin films, powder) vary from 1.58 up to 3.14 eV [53].…”

Characterization and physical property studies of Sn, Al doped and co-doped CdO thin films

“…Many processes may be used to obtain un-doped, doped CdO thin films including pulsed laser deposition [11], thermal evaporation [12], sputtering [13], sol-gel [14], Metalloorganic chemical vapor deposition (MOCVD) [15], electrospinning [16], and spray pyrolysis [17]. Among these approaches, spray pyrolysis remains appealing and interesting due to its low cost, simplicity, speed, and ability to create large-area coatings.…”