Raman and IR studies of BaBi₂Ta₂O₉ prepared by a sol–gel process

Abstract

The formation of ferroelectric BaBi 2 Ta 2 O 9 (BBT) by a sol-gel process was studied by X-ray, Raman and infrared (IR) spectroscopy. Our results show that the formation of a Bi-layered phase proceeds via an intermediate fluorite-type phase. This method allows obtaining a BBT phase already at 750 • C. This temperature is about 150-200 • C lower than that required in the conventional solid-state reaction. Therefore, a material with smaller particle size can be obtained. Raman and IR studies of the obtained Bi-layered phase show that phonon properties of the synthesized particles are slightly different from those of the bulk material due to the size effect, defects and weak changes in local order. Temperature dependence of Raman and IR wavenumbers is consistent with the orthorhombic distortion of the BBT structure.

Synthesis of Eu3+‐doped BaBi2Ta2O9 based glass‐ceramic nanocomposites: Optical and dielectric properties

“…No Joint Committee on Powder Diffraction Standards (JCPDS) card file corresponding to the diffraction patterns for the crystalline BBT phase is available. The diffraction patterns of the crystalline BBT phase are confirmed from literature data . Two crystalline phases could be identified; the major crystal phase is BaBi 2 Ta 2 O 9 (BBT) (represented as X in Figure ) and a minor secondary phase of stoichiometry Ba 3 Si 4 Ta 6 O 23 (represented as Y in Figure ) was observed.…”

“…The diffraction patterns of the crystalline BBT phase are confirmed from literature data. 15,17 Two crystalline phases could be identified; the major crystal phase is BaBi 2 Ta 2 O 9 (BBT) (represented as X in Figure 3) and a minor secondary phase of stoichiometry Ba 3 Si 4 Ta 6 O 23 (represented as Y in Figure 3) was observed. With the increase in ceramization time, the intensity of diffraction peaks of both the phases was increased.…”

“…A significant amount of research work on the ferroelectric and dielectric properties of BBT have been reported, where BBT single crystals, ceramics and thin films have been synthesized by methods such as conventional solid‐state reaction,co‐precipitation technique, metal‐organic decomposition method, sol‐gel technique and milling in a vibratory mill . Compared to ferroelectric ceramics, glass–ceramic dielectrics are well‐known for very low or zero porosity, possessing higher dielectric constant and breakdown strength .…”

“…8 A member of this Aurivillius family, BBT consists of two perovskite-like layers with composition [(BaTa 2 O 7 ) 2À ] interspersed between [(Bi 2 O 2 ) 2+ ] layers with Ba (II) cations being located between the corner sharing TaO 6 octahedra, within the perovskite-like layer 9 having tetragonal (D 4h ) crystal structure with I4/mm space group. 10,11 A significant amount of research work on the ferroelectric and dielectric properties of BBT have been reported, where BBT single crystals, ceramics and thin films have been synthesized by methods such as conventional solidstate reaction, [12][13][14] co-precipitation technique, 15 metalorganic decomposition method, 16 sol-gel technique 17 and milling in a vibratory mill. 18 Compared to ferroelectric ceramics, glass-ceramic dielectrics are well-known for very low or zero porosity, possessing higher dielectric constant and breakdown strength.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part VI

“…using Raman scattering and DFT calculations . Maczka and co‐workers published three studies of IR and Raman structural characterizations of the crystals TaWO 5.5 , ASbWO 6 (A═K, Rb, Cs, Tl), and ASbWO 6 −H 2 O (A═H, NH 4 , Li, Na) pyrochlore oxides, BaBi 2 Ta 2 O 9 prepared by a sol–gel process, and K 4 Nb 6 O 17 and K 4 Nb 6 O 17 −3H 2 O single crystals . Manciu et al .…”