Abstract Considerable efforts have been made to explore high-dielectric constant ceramics for their promising applications as high-energy density capacitors and fine metal-oxide-semiconductor field effect transistors. Here, we investigated the colossal dielectric behaviors of TiO2-x ceramics influenced by defect dipoles introduced by oxygen vacancies and Ti3+. As temperature decreases from room temperature, three thermally activated relaxations were observed. A room temperature relaxation (R3) was attributed to Maxwell-Wagner relaxation due to the electrode/sample contact. A low-temperature Maxwell-Wagner relaxation (R1) featuring nearly constant loss behavior was associated with frozen carriers. The middle-temperature relaxation (R2) was verified to be the polaron relaxation composed of two segment contributions: polaron hopping and polaron reorienting. The defect dipoles gradually changed from a disordered state into an ordered state in external electric field when temperature falls and reaches a frozen-in state below 217 K. The ordered phase will turn into disordered again when temperature increases to 217 K due to thermal perturbation corresponding to a phase transition. These results indicate that the colossal dielectric constant properties of TiO2 system are attributed to defect dipole clusters. This work exhibits a way to identify the dipole effect. Moreover, we found that the dielectric properties of TiO2-x ceramics hardly depend on temperature and frequency. This implies that TiO2-x ceramics is a kind of promising colossal dielectric materials which can work at various temperatures.

中文翻译：

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缺陷偶极子对TiO2-陶瓷巨介电行为的影响

摘要 为了探索高介电常数陶瓷作为高能量密度电容器和精细金属氧化物半导体场效应晶体管的有前景的应用，已经做出了相当大的努力。在这里，我们研究了由氧空位和 Ti3+ 引入的缺陷偶极子对 TiO2-x 陶瓷的巨大介电行为的影响。随着温度从室温降低，观察到三个热激活弛豫。由于电极/样品接触，室温弛豫 (R3) 归因于 Maxwell-Wagner 弛豫。具有几乎恒定损耗行为的低温 Maxwell-Wagner 弛豫 (R1) 与冷冻载体有关。中温弛豫 (R2) 被证实是由两个部分贡献组成的极化子弛豫：极化子跳跃和极化子重定向。当温度下降并在217 K以下达到冻结状态时，缺陷偶极子在外部电场中逐渐从无序状态转变为有序状态。当温度升高到217 K时，由于相应的热扰动，有序相将再次变为无序状态到相变。这些结果表明 TiO2 系统的巨大介电常数特性归因于缺陷偶极簇。这项工作展示了一种识别偶极效应的方法。此外，我们发现 TiO2-x 陶瓷的介电性能几乎不依赖于温度和频率。这意味着 TiO2-x 陶瓷是一种很有前途的巨大介电材料，可以在各种温度下工作。当温度下降时，缺陷偶极子在外部电场中逐渐从无序状态变为有序状态，并在 217 K 以下达到冻结状态。当温度升高到 217 K 时，由于相应的热扰动，有序相将再次变为无序状态。到相变。这些结果表明 TiO2 系统的巨大介电常数特性归因于缺陷偶极簇。这项工作展示了一种识别偶极效应的方法。此外，我们发现 TiO2-x 陶瓷的介电性能几乎不依赖于温度和频率。这意味着 TiO2-x 陶瓷是一种很有前途的巨大介电材料，可以在各种温度下工作。当温度下降并在217 K以下达到冻结状态时，缺陷偶极子在外部电场中逐渐从无序状态转变为有序状态。当温度升高到217 K时，由于相应的热扰动，有序相将再次变为无序状态到相变。这些结果表明 TiO2 系统的巨大介电常数特性归因于缺陷偶极簇。这项工作展示了一种识别偶极效应的方法。此外，我们发现 TiO2-x 陶瓷的介电性能几乎不依赖于温度和频率。这意味着 TiO2-x 陶瓷是一种很有前途的巨大介电材料，可以在各种温度下工作。