28th Congress of SCTM

SYNTHESIS AND INVESTIGATION OF La1xErxMn0.5Fe0.5O3 (x = 0.2 and 0.4) COMPLEX PEROVSKITES

Not scheduled

10m

Metropol Lake Resort

E-poster Physical, structural chemistry, spectroscopy and electrochemistry

Speaker

Ms Cvetanka Trajkovska (Institute of Chemistry, Faculty for Natural Sciences and Mathematics , University "Ss. Cyril and Methodius", Skopje, North Macedoina)

Description

In recent decades, perovskite-type ceramic materials, with general formula ABO3, have attracted considerable attention due to their significant electrical, optical, magnetic and catalytic properties. Among them, mixed-cation perovskites containing two different lanthanide ions at the A-site and two transition-metal ions at the B-site have attracted particular attention because their structural and functional properties can be effectively tuned through cation substitution. In this work, the synthesis and characterization of La1xErxMn0.5Fe0.5O3 (x =0.2 or 0.4) are presented.
These compounds were synthesized by the sol-gel combustion method using citric acid as fuel, while the pH value of the precursor solution was adjusted with ammonia. The obtained perovskite precursors were calcined at 900 °C for 8 hours to obtain the crystalline perovskite phase.
Powder X-ray diffraction (PXRD) confirmed the successful formation of single-phase perovskites with high phase purity and crystallinity, and revealed a systematic shift of the diffraction peaks with increasing of Er3+ content.
The morphology and the verification of the stoichiometry of the synthesized perovskites were performed by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDX analysis). The EDX results showed good agreement with the proposed composition. SEM micrographs revealed a typical sponge-like porous morphology characteristic for perovskites obtained by sol-gel combustion method.
In addition to structural investigations, Fourier-transform infrared (FTIR) in the mid- and far-IR regions confirmed the presence of characteristic stretching and bending vibrations of Mn/Fe–O, and Ln/Er–O. The Raman spectra of both compositions exhibit similar vibrational features in the 200–700 cm⁻¹ region, indicating similar local environments around the (Mn,Fe)O6 octahedra. The observed broad Raman bands suggest the presence of local structural disorder and distortion of the (Mn,Fe)O6 octahedra, most likely arising from the Jahn–Teller activity of Mn3+ ions together with the random distribution of Mn and Fe cations over the B-sites of the perovskite lattice.

Keywords: Complex perovskites, PXRD, SEM/EDX, FTIR, Raman spectroscopy