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研究了不同制备压力下成型的以金红石相为主的纳米二氧化钛介电常数的频率谱和温度谱。在频率谱上发现,当频率ω<0.1kHz时,随着测量频率的下降,介电常数迅速升高,低频下的介电常数比高频区的介电常数高1—2个数量级。并且随着样品加压压力的提高,介电常数升高,在与之相对应的介电损耗谱上,随着样品加压压力的提高,损耗值下降,损耗峰向低频区位移。对1.0GPa压力下成型的样品,其介电常数随测量温度的升高,分别在50℃和300℃出现两个峰值。经分析得出,影响金红石相纳米二氧化钛介电行为的微观机制主要为晶粒内部的电子松弛极化和界面中的电偶极矩的转向极化,50℃峰对应于电于松弛极化,而300℃峰则对应于电偶极矩的转向极化。The spectra of the dielectric constant vs. the measuring temperature and of the dielectric constant vs. the measuring frequency for the nanostructured rutile bulk samples prepared under different pressures were investigated. It can be observed that when the measuring frequency ω2 times higher than that in the high frequency range. Furthermore, with the increment of the pressure, the dielectric constant rises and dielectric loss decreases and shifts towards the low frequency. For the samples formed under 1.0 GPa, two peaks appear in the spectrum of dielectric constant vs. the measuring temperature, and their peak positions are 50℃ and 300℃ , respectively. According to dielectric polarization theory, it can be supposed that high dielectric constant of nanostructured rutile arises mainly from the electronic relaxation polarization, which takes place inside the particle components of nanostructured rutile, and the rotation direction polarization, which is established in interfaces of nanostructured rutile, The 50℃ peak and the 300 ℃ peak are, respectively, attributed to the electronic relaxation polarization and the rotation direction polarization.
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