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摘要
Textured Sr0.63Ba0.37Nb2O6 ferroelectric ceramics, with relaxor characteristics, were fabricated by the hot forging process. The analysis of the complex dielectric constant as a function of the temperature revealed the presence of three dielectric anomaly regions. In addition, the relaxor behaviour of this ceramic was also observed at microwave frequencies, evidencing the existence of active polar regions in a broad frequency range. Using the Vogel-Fulcher approximation, physical parameters such as the freezing temperature (T-f) were estimated. It was verified that the mechanisms of the dielectric response, in the microwave frequency range, are also affected by the presence of compositional fluctuations and local electric fields. A phenomenological equation was applied in order to investigate the nature of the polarization mechanisms at low frequencies. Also, a qualitative model was proposed to explain the anisotropic behaviour observed in the phase transition diffuseness between the different ceramic directions.
- 出版日期2007-1-17
