Far-infrared reflection spectra of Ba(Mn1/3Ta2/3)O3 sintered in nitrogen and in air

Far-Infrared Study of BaTi4O9 Microwave Dielectric Ceramics

“…7,8) Under such an assumption, some investigations into the relationship between microwave dielectric properties and lattice vibrations have been carried out especially for compounds with a complex perovskite structure and a chemical formula of A(B 0 1=3 B 00 2=3 )O 3 (A ¼ Ba; B 0 ¼ Mg, Zn; B 00 ¼ Nb, Ta, etc.). [8][9][10][11][12] Results of these studies indicate, for those microwave dielectric ceramics with a moderate dielectric constants (20 -50), the calculated dielectric constants agree well with the measured ones, while the calculated dielectric losses are 2 -3 times lower than the measured ones. 13) However, BaTi 4 O 9 has quite a different structure, with a space group (Pmmn, No.…”

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

“…Since the dielectric properties at microwave frequencies are mainly contributed from the ionic polarization, the study of phonon vibration spectra of Ba(B 1/3 B 2/3 )O 3 has been of particular interest [5][6][7][8][9][10][11][12]. Recently, the Raman phonons [13] and the normal mode for resonant peaks in FTIR spectra [14] in Ba(Mg 1/3 Ta 2/3 )O 3 -Ba(Mg 1/3 Nb 2/3 )O 3 , BMT-BMN, materials were unambiguously identified.…”

Correlation of microwave dielectric properties and normal vibration modes of xBa(Mg1/3Ta2/3)O3–(1−x)Ba(Mg1/3Nb2/3)O3 ceramics: II. Infrared spectroscopy

“…4 Since the dielectric properties at microwave range follow mainly from ionic polarization, the phonon vibration spectra of Ba(B 1/3 Ј B 2/3 Љ )O 3 have been of particular interest. [5][6][7][8][9][10][11][12][13] H. Tamura et al 5 first analyzed the vibration of 1:2 ordered Ba(Zn 1/3 Ta 2/3 )O 3 normal modes, and Siny et al 6 investigated the Raman spectra of several complex perovskites, proposing the existence of short-range 1:1 order in Ba(Mg 1/3 Ta 2/3 )O 3 . Recently, the Raman phonons in Ba(Mg 1/3 Ta 2/3 )O 3 -Ba(Mg 1/3 Nb 2/3 )O 3 materials were clearly identified.…”

“…They thus determine the dielectric properties in the microwave region. [7][8][9][10][11][12][13] Based on the observation of simple perovskite Pm3m structures, 14,15 the FTIR spectrum of complex perovskite with 1:2 long-range order can be divided into three regimes: ͑i͒ frequencies around 150 cm Ϫ1 correspond to the vibration between the cation and the BO 6 octahedron; ͑ii͒ intermediate bands at 150-500 cm Ϫ1 are mostly related to the B-O stretching mode, and ͑iii͒ high-frequency bands above 500 cm Ϫ1 are correlated with the O-B-O bending mode. The distortion of the BO 6 octahedron in complex perovskite causes the triple-degenerate vibration mode ͑F mode͒ in simple perovskite to split into a double degenerate and a non-degenerate modes ͑E and A modes͒.…”