This paper presents the results of studies of a low-frequency vibration spectrum of PbCo1/3Nb2/3O3 (PCN) relaxor ferroelectric crystal using the Brillouin and Raman light scattering in the temperature range from 80 to 750 K. The analysis of the temperature behaviour of the longitudinal acoustic (LA) phonon in Brillouin scattering spectra showed no anomalies in the vicinity of "diffuse phase transition" (Тm = 256 К) in PCN. Polarized Raman light scattering spectra were obtained in PCN over the entire temperature range studied. Analysis of low-frequency optical mode behaviour in PCN during temperature change also revealed no correlations with dielectric permeability anomaly in the vicinity of Тm: softening of optical phonon at 43 cm-1 frequency in VV polarization is observed at 150 K. In the same temperature range, there are anomalies (a "narrow" and weak component) in quasi-elastic scattering (QELS) obtained in temperature behaviour with VH polarization in Raman spectra in PCN. A "wide" and intense QELS component, obtained in Raman spectra with VV polarization, shows anomalies in the vicinity of Tm. We associate the anomalies of optical phonons and QELS with structure distortions in the formation of phase stratification and the dynamics of polar nano-regions.

中文翻译：

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弛豫铁电 PbCo1/3Nb2/3O3 低频振动谱的非弛豫行为：来自布里渊和拉曼散射测量的证据

本文介绍了使用布里渊和拉曼光散射在 80 到 750 K 温度范围内对 PbCo1/3Nb2/3O3 (PCN) 弛豫铁电晶体低频振动光谱的研究结果。布里渊散射光谱中的纵向声学 (LA) 声子在 PCN 中的“扩散相变”(Тm = 256 Ð) 附近没有显示异常。在研究的整个温度范围内，在 PCN 中获得了偏振拉曼光散射光谱。温度变化期间 PCN 中低频光学模式行为的分析也显示与 Тm 附近的介电渗透率异常没有相关性：在 150 K 观察到 VV 极化中 43 cm-1 频率的光学声子软化。在相同温度下范围，在 PCN 的拉曼光谱中具有 VH 偏振的温度行为中获得的准弹性散射 (QELS) 中存在异常（“窄”和弱分量）。在具有 VV 偏振的拉曼光谱中获得的“宽”和强 QELS 分量显示了 Tm 附近的异常。我们将光学声子和 QELS 的异常与相分层形成中的结构畸变和极性纳米区域的动力学联系起来。