Banca de QUALIFICAÇÃO: JOSE BRUNO MARQUES FERREIRA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : JOSE BRUNO MARQUES FERREIRA
DATE: 19/02/2026
TIME: 13:30
LOCAL: Auditório da UAF
TITLE:

Effect of Atomic Substitution of Cobalt in CdT iO3 by the Solid State Reaction Method

KEY WORDS:

Raman spectroscopy; Energy gap; Solid-state reaction.

PAGES: 40
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

This work aims to study the structural, vibrational, and optical properties of ABO3-type ceramic compounds by investigating the atomic substitution of cobalt (Co2+) in cadmium titanate (CdT iO3). The interest lies in understanding how the interaction between these ions modifies the CoxCd1−xT iO3 system at concentrations ranging from x = 0.0 to 1.0, aiming to modulate the material’s band gap and reduce the toxicity impacts associated with cadmium. The synthesis was performed via the solid-state reaction method using vibro-mechanical milling, with calcination temperatures determined by Vegard’s law to ensure the formation of the desired phases. CdT iO3 is a material that can crystallize in both ilmenite and perovskite phases, while CoT iO3 possesses an ilmenite structure. To characterize the evolution of these structures, X-ray diffraction (XRD), Raman spectroscopy, and optical spectroscopy in the UV-Vis-NIR region were employed. The XRD and Raman results for the reference samples confirmed agreement with reports in the literature. It was found that the substitution of Cd2+ by Co2+ causes a reduction in the Goldschmidt tolerance factor, indicating increased distortion in the crystal lattice. Furthermore, optical absorption measurements revealed a shift of the absorption edge toward lower energies with increasing cobalt concentration, reducing the energy gap to values near 1.8 eV. It is expected that the results obtained for the CoxCd1−xT iO3 system can contribute to the development of new technologies in sensors, capacitors, and photocatalytic devices, assisting in the elucidation of physical and chemical phenomena in ABO3-type titanates.

 

COMMITTEE MEMBERS:
Externo à Instituição - ISAAC DE MACEDO FELIX
Interno - 2341246 - KENNEDY LEITE AGRA
Presidente - 1702795 - RENILTON CORREIA DA COSTA