Experimental study and DFT calculations of improved giant dielectric properties of Ni2+/Ta5+ co-doped TiO2 by engineering defects and internal interfaces
Experimental study and DFT calculations of improved giant dielectric properties of Ni2+/Ta5+ co-doped TiO2 by engineering defects and internal interfaces
复制标题
通过工程缺陷和内部界面改善Ni2/Ta5共掺杂TiO2巨介电性能的实验研究和DFT计算
DOI：
10.1016/j.jeurceramsoc.2022.05.037
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发表时间：
2022
影响因子：
5.7
通讯作者：
Thongbai Prasit
中科院分区：
文献类型：
--
作者：
Thongyong Nateeporn;Chanlek Narong;Srepusharawoot Pornjuk;Takesada Masaki;Cann David P.;Thongbai Prasit
具有优异介电性能的高性能陶瓷具有化学式（Ni 1/3 Ta 2/3）xTi 1 − xO 2。Ni 2+和Ta 5+的掺杂导致了TiO 2中氧空位和自由电子的形成。（Ni 1/3 Ta 2/3）xTi 1 − xO 2具有0.046的低损耗角正切和3.5-4.5 × 104的高介电常数，对温度的依赖性非常弱（−60至200 °C）。宽带介电谱显示，在− 253-210 °C的温度范围内，介电弛豫响应至少有四个主要来源。DFT计算表明缺陷簇的形成，这是介电响应的最大贡献者，并且即使在-253 °C的温度下也是主要的。陶瓷中的晶界和表面层机制都有助于在相对较高的温度下的介电响应。在高于150 °C的高温下，与氧空位扩散相关的样品-电极接触效应占主导地位。
High-performance ceramics with chemical formula (Ni1/3Ta2/3)xTi1−xO2with excellent dielectric properties are demonstrated. The dopants of Ni2+and Ta5+in TiO2caused the formation of oxygen vacancies and free electrons. The (Ni1/3Ta2/3)xTi1−xO2exhibited low loss tangent of 0.046 and a high dielectric permittivity of 3.5–4.5 × 104with a very weak dependence on temperature (−60 to 200 °C). Broadband dielectric spectroscopy shows at least four dominant sources in the dielectric relaxation response in the temperature range of − 253–210 °C. DFT calculations indicate the formation of defect clusters, which are the largest contributors to the dielectric response, and these are found to be dominant even at temperatures down to − 253 °C. Both grain boundary and surface layer mechanisms in the ceramics contribute to the dielectric response at the relatively high temperatures. The sample–electrode contact effect associated with oxygen vacancy diffusion is dominant at high temperatures above 150 °C.