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

Abstract

Micro-Raman measurements of xBa(Mg1/3Ta2/3)O3–(1−x)Ba(Mg1/3Nb2/3)O3 perovskite ceramics, with x=0, 0.25, 0.50, 0.75, and 1.0, were taken at room temperature. Raman results clearly show the 1:2 ordered structures of these compounds. Four A1g and five Eg Raman modes were unambiguously assigned. The A1g(O) phonon of the oxygen-octahedron stretch mode, which possesses the largest energy and width of all the observed Raman phonons, significantly influences the microwave dielectric properties of the materials. A higher vibration frequency of A1g(O) mode results in a lower dielectric constant, and a wider width of the mode corresponds to a lower Q×f value.

Microwave Dielectric Mechanism Studied by Microwave Near-Field Microscopy and Raman Spectroscopy

“…As shown in Fig. 4(a), the A 1g [O] breathing mode is related to the rigidity of B'O 6 octahedra in complex perovskite, which dominates the polarization mechanism contributing to the dielectric response at microwave frequencies [4,14]. It should be noted that the contrast observed in Fig.…”

“…Since the correlation of the microwave properties and lattice vibrational modes for BMT complex perovskite has been unambiguously performed recently [4,14], the mapping of EMP resonant frequency and micro-Raman spectrum intensity for a high-dielectricconstant (low-resonant-frequency) region of BMT The spatial resolution achievable in EMP measurement is about sub-micrometer, which is higher than that in micro-Raman spectrum, so we can see more detailed structure in Fig. 3(a).…”

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

“…2 reveals that all the samples possess very sharp phonon resonance peak, indicating again that these materials are highly ordered. The Raman active modes have been unambiguously assigned [13] and are listed in Table 1(a), in which the effect of Sr-incorporation on the characteristics of the BMT materials is also summarized. Among the major Raman peaks observed in Fig.…”

“…The dielectric properties were calculated from Kramers-Kronig analysis of the reflectance data [13]. Raman measurements were performed at room temperature, and signals were recorded by a DILOR XY-800 triple grating Raman spectrometer with the resolution around 0.5 cm −1 .…”

“…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. The change in microwave dielectric properties of the BMT-BMN materials with the composition has been correlated with the modification on Raman and FTIR spectroscopic characteristics.…”