Correlation of Microwave Dielectric Properties and Normal Vibration Modes of Ba(Mg1/3Ta2/3)O3-Series Materials

Abstract

Microwave dielectric properties of Ba(Mg 1/3 Ta 2/3 )O 3 -series materials were investigated using Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The normal vibration modes of these spectra were assigned, and the origin of dielectric response of the materials was deduced. Among the prominent normal vibration modes in the FTIR spectra, those which correlated with O-layers and Ba-layers change with Sr-ratio most significantly, whereas in micro-Raman measurements, the A 1g (O) phonon of oxygen-octahedron stretch mode changes with Sr-ratio most profoundly. These results reveal clearly the close relationship between the characteristics of FTIR and Raman spectra of the BMT-series materials and their microwave dielectric properties.

Effects of Zinc Substitution on Crystal Structure and Microwave Dielectric Properties of CaLa4Ti5O17 Ceramics

“…The volatilization of ZnO was reduced due to the decrease in sintering temperature. Thus, Zn 21 occupied the A site of the perovskite structure, substituting the absent Ca 21 . This kind of substitution made the change in lattice parameters undetectable.…”

“…It is interesting that the A 1g mode band appears in the case of only one B-site cation type (Ti 41 ), which is similar to the Ba 5 Nb 4 O 15type hexagonal perovskites, 19 but different from most of the other B-site perovskites. 20,21 It was generally considered that the A 1g mode band is not Raman active if there is only one B-site cation species. 20 This may not be true for perovskites with special characteristics, such as Ba 5 Nb 4 O 15 -type hexagonal perovskites, and the present compounds.…”

“…X-ray diffraction and Raman spectra analysis reveal that with increasing zinc content, the n value of the A n B n O 3n12 structures changed and distinct compounds formed. With increasing Zn 21 content, the perovskite-slabs decreased from 5-[BO 6 ] to 4.5-[BO 6 ] in the range of 0.13rxr0.2, and then collapsed to 4-[BO 6 ] at about x 5 0.6, with Zn 2 TiO 4 as the secondary phase. The microwave dielectric properties of the sintered ceramics vary with the Zn 21 content.…”

Improvement on the characteristic of Ba2Ti9O20 microwave dielectric materials prepared by modified co-precipitation method

“…It is known that sharper lattice vibration modes for the materials usually lead to higher (Q × f)-value. 15,16 Meanwhile, the inferior lattice vibration characteristics for the air-sintered samples can be ascribed to the incompletely developed grains for the materials, which is implied by the roundish-rod geometry of the grains in these materials.…”

Investigation of microwave dielectric properties in the BaO–Nb2O5–P2O5 system

“…Among various dielectric compositions, complex perovskite compounds such as Ba(Mg 1/3 Ta 2/3 )O 3 and Ba(Zn 1/3 Ta 2/3 )O 3 are known to have the best microwave dielectric properties for future trends [8][9][10]. However, research focused on discovering new compositions is still active as there is a great demand for a variety of permittivity, low cost, and low firing conditions.…”