Synthesis and Structural Characterization of Nanocrystalline Batio3 at Various Calcination Temperatures

Abstract

Barium titanate (BaTiO 3 ) powders with particle sizes about 50 nm in diameter were synthesized using a hydrothermal route. The powders were characterized using various experimental techniques such as XRD, TEM and Raman spectroscopy, and they showed a good crystallinity and homogeneity without heat treatments. Also, Raman spectra showed the presence of the tetragonal phase. In addition, various calcination treatments were made to BaTiO 3 powders with the purpose to improve their ferroelectric properties. In general, calcination treatments improved the crystallinity and homogeneity of the samples considerably but did not modify the internal structure of the BaTiO 3 , which was observed in the Raman spectra. On the other hand, from theoretical calculations were established that the cubic phase should be better dielectric in comparison with the tetragonal phase, but this latter would have better optical properties. However, experimental evidences are indicative that the cubic phase would predominate in the synthesis of the compound.

Absence of ferromagnetism in ferroelectric Mn‐doped BaTiO3 nanofibers

“…Table shows a summary of the measured Raman peaks, as well as the calculated vibrational modes for the pure structure, with their respective irreducible representations, where a very good agreement between experimental and calculated values can be seen. Most of the irreducible representations assigned in this work coincide well with other authors, except for the vibrating mode measured at 257 cm −1 , and calculated at 273 cm −1 , that can be assigned to mode B 1 , while others authors identify it as an A 1 mode. This peak is still present in doped structure, although it has been widened and appears at ~266 cm −1 .…”

Efficient Cocatalyst-Free Piezo-Photocatalytic Hydrogen Evolution of Defective BaTiO3–x Nanoparticles from Seawater

“…The main features observed include a small peak at 175 cm –1 [A 1 (TO), E­(LO)], a broad peak centered at 265 cm –1 [A 1 TO], a relatively sharp peak at 306 cm –1 [B 1 , E­(TO + LO)], a broad sharp peak centered at 520 cm –1 [A 1 , E­(TO)], and a small broad peak centered at 720 cm –1 [A 1 , E­(LO)] . It is well-established that cubic BTO is Raman-inactive owing to the isotropic distribution of electrostatic forces around the centrosymmetric Ti 4+ ion. , The appearance of characteristic Raman peak at 306 cm –1 confirms the XRD identification of tetragonal BTO. The Raman-active nature of tetragonal BTO derives from the electronic/ionic polarization caused by the off-centered displacement of the Ti 4+ cation within the TiO 6 octahedron, which results in ferroelectric and consequent piezocatalytic behavior …”

“…The main features observed include a small peak at 175 cm −1 [A 1 (TO), E(LO)], a broad peak centered at 265 cm −1 [A 1 TO], a relatively sharp peak at 306 cm −1 [B 1 , E(TO + LO)], a broad sharp peak centered at 520 cm −1 [A 1 , E(TO)], and a small broad peak centered at 720 cm −1 [A 1 , E(LO)]. 23 It is wellestablished that cubic BTO is Raman-inactive owing to the isotropic distribution of electrostatic forces around the centrosymmetric Ti 4+ ion. 21,23 The appearance of characteristic Raman peak at 306 cm −1 confirms the XRD identification of tetragonal BTO.…”

“…23 It is wellestablished that cubic BTO is Raman-inactive owing to the isotropic distribution of electrostatic forces around the centrosymmetric Ti 4+ ion. 21,23 The appearance of characteristic Raman peak at 306 cm −1 confirms the XRD identification of tetragonal BTO. The Raman-active nature of tetragonal BTO derives from the electronic/ionic polarization caused by the offcentered displacement of the Ti 4+ cation within the TiO 6 octahedron, 16 which results in ferroelectric and consequent piezocatalytic behavior.…”

Theoretical investigation of electronic, optical and thermoelectric properties of tellurium doped barium titanate (BTO) through modified Becke – Johnson exchange potential

“…Barium titanate (BaTiO 3 ) is one of the most prominent perovskite crystals, which has been the subject of many experimental and theoretical investigations. As an example, Fuentes et al [9] prepared BaTiO 3 powders using a sol-gel-hydrothermal process to study its effects at different times and calcination temperatures. Ali et al [10] prepared La-doped BaTiO 3 thin films and studied the composition of the films.…”