Microwave properties of Ba(Mg1/3Ta2/3)O3, Ba(Mg1/3Nb2/3)O3 and Ba(Co1/3Nb2/3)O3 ceramics revealed by Raman scattering

Correlation between dielectric properties and vibration modes of xCaF2–Ag(Nb,Ta)O3 materials

“…The xCaF 2 -ANT (x = 4 wt.%) sample with low dielectric loss shows broad FWHM of A 1g (O) mode. These indicate that the physical properties of oxygen octahedra have strong influences on dielectric properties, which is consistent with that reported by Chen et al [25]. …”

Structure and microwave dielectric properties of Ba[(Mg 1−x Ni x ) 1/3 Nb 2/3 ]O 3 ceramics

“…On one hand, the higher binding energy of Ni 3+ than that of Ni 2+ makes the crystal lattice more rigid, thus improves the Q×f value, on the other hand, Ni 3+ also makes negative contribution to the cations ordering as discussed above, which should deteriorate the Q×f value, the combined effect is difficult to be determined and requires further investigation. The same occurs for r and f, since a more rigid crystal lattice has lower r and more negative f, while a disordering state has higher r and more positive f [6,39]. It should be pointed out that the analysis above needs to be further confirmed by more precise experiments which are beyond the present study.…”

Effects of BaWO4 additive on Raman phonon modes and structure–property relationship of Ba(Mg1/3Ta2/3)O3 microwave dielectric ceramics

“…Raman spectra of BMT-BW ceramics ranging from 50 cm À1 to 900 cm À1 in room temperature are presented in Fig. 3, which are indexed according to the previous studies of BMT [23,25].…”

“…3, the spectral profiles of the samples are similar to each other and six Raman modes can be observed in the spectra. Four main assigned lines, which are concerned with the spectra of the 1:1 ordered nanoscale regions of P 3m1 symmetry [23,25], are indexed as follows: the F 2g (Ba) [E g (Ba) + A 1g (Ba)] modes near 104 cm À1 ; F 2g (O) modes near 383 cm À1 ; E g (O) modes near 430 cm À1 ; and A 1g (O) modes near 790 cm À1 . Besides, two other peaks are observed, i.e., E g (O) modes near 157 cm À1 and E g (Ta) modes near 206 cm À1 , which have been identified as 1:2 ordered structure-related vibrations [26].…”