中国物理B ›› 2012, Vol. 21 ›› Issue (1): 17803-017803.doi: 10.1088/1674-1056/21/1/017803

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

A polarized micro-Raman study of a 0.65PbMg1/3Nb2/3O3–0.35PbTiO3 single crystal

张丽艳, 朱恪, 刘玉龙   

  1. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
  • 收稿日期:2011-06-21 修回日期:2011-10-27 出版日期:2012-01-15 发布日期:2012-01-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 10674171 and 10874236).

A polarized micro-Raman study of a 0.65PbMg1/3Nb2/3O3–0.35PbTiO3 single crystal

Zhang Li-Yan(张丽艳), Zhu Ke(朱恪), and Liu Yu-Long(刘玉龙)†   

  1. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2011-06-21 Revised:2011-10-27 Online:2012-01-15 Published:2012-01-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 10674171 and 10874236).

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摘要： Polarized micro-Raman spectra of a 0.65PbMg1/3Nb2/3O3-0.35PbTiO3 (0.65PMN-0.35PT) single crystal poled in the [001] direction are obtained in a wide frequency range (50-2000 cm-1) at different temperatures. The best fit to the Raman spectrum at 77 K is achieved using 17 Lorenzians to convolute into it, and this is proved to be a reasonable fit. According to the group theory and selection rules of overtone and combinational modes, apart from the seven Raman modes that are from first-order Raman scattering, the remaining ones are attributed to being from second-order Raman scattering. A comparison between the experimental results and theoretical predictions shows that they are in satisfactory agreement with each other. Our results indicate that at 77 K the sample belongs to the rhombohedral symmetry with the C3v5 (R3m) space group (Z=1). In our study, on heating, the 0.65PMN-0.35PT single crystal undergoes a rhombohedral to tetragonal to cubic phase transition sequence. The two phase transitions occur at 340 and 440 K, which correspond to the disappearance of the soft mode near 106 cm-1 recorded in VV polarization and the vanishing of the band around 780 cm-1 in VH polarization, respectively.

关键词: 0.65PMN-0.35PT, polarized micro-Raman, second-order Raman scattering, phase transition

Abstract: Polarized micro-Raman spectra of a 0.65PbMg1/3Nb2/3O3-0.35PbTiO3 (0.65PMN-0.35PT) single crystal poled in the [001] direction are obtained in a wide frequency range (50-2000 cm-1) at different temperatures. The best fit to the Raman spectrum at 77 K is achieved using 17 Lorenzians to convolute into it, and this is proved to be a reasonable fit. According to the group theory and selection rules of overtone and combinational modes, apart from the seven Raman modes that are from first-order Raman scattering, the remaining ones are attributed to being from second-order Raman scattering. A comparison between the experimental results and theoretical predictions shows that they are in satisfactory agreement with each other. Our results indicate that at 77 K the sample belongs to the rhombohedral symmetry with the C3v5 (R3m) space group (Z=1). In our study, on heating, the 0.65PMN-0.35PT single crystal undergoes a rhombohedral to tetragonal to cubic phase transition sequence. The two phase transitions occur at 340 and 440 K, which correspond to the disappearance of the soft mode near 106 cm-1 recorded in VV polarization and the vanishing of the band around 780 cm-1 in VH polarization, respectively.

Key words: 0.65PMN-0.35PT, polarized micro-Raman, second-order Raman scattering, phase transition

中图分类号:  (Infrared and Raman spectra)

  • 78.30.-j
77.80.B- (Phase transitions and Curie point) 77.80.Jk (Relaxor ferroelectrics)