Applied Physics A ( IF 2.5 ) Pub Date : 2021-09-02 , DOI: 10.1007/s00339-021-04864-4 Prasad Narayan Patil 1 , Uma Subramanian 1 , Rajeshkumar Shankar Hyam 1
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Powdered xBaWO4/(1 − x)CaWO4 where (x = 0,0.25,0.5,0.75,1) nanocomposites were synthesized by the co-precipitation method at room temperature (RT). We are reporting DC and AC conductivity and dielectric properties of nanocomposites at room temperature (RT). Structural characterization and HRTEM image confirm interface formation of the nanocomposites. The current density–electric field (i.e., J–E) characteristics of the nanocomposites’ studies reveal excellent varistor behavior. Dielectric properties were measured in the frequency 20 Hz–3 MHz at room temperature (RT). The dielectric constant was found to be higher for C2 (0.5BaWO4/0.5CaWO4) nanocomposites as compared to single phase and was maximum for atomic ratio (Ba/Ca) with optimal value of ‘x’. DC conductivity (σdc), calculated from Jonscher’s power law, of C2 (0.5BaWO4/0.5CaWO4) nanocomposites interfaced is higher than that of single phase, respectively. Enhanced AC conductivity is also observed for C2 (0.5BaWO4/0.5CaWO4) nanocomposites. These enhanced electrical properties of C2 (0.5BaWO4/0.5CaWO4) nanocomposites are due to the space charge layer (SCL) formation at the interface. In detail, conduction models for all the nanocomposites are explained. Thermopower investigations on the nanocomposites resulted in Seebeck coefficient (S) showing a transition from negative to positive values with confirmation n-type semiconductors at room temperature (RT). The enhanced power factor of C3 (0.75BaWO4/0.25CaWO4) nanocomposites is at higher temperature as compared to other nanocomposites. This C2 (0.5BaWO4/0.5CaWO4) nanocomposite can be considered as an efficient multifunctional nanocomposites due to its enhanced optical and electrical properties, and C3 (0.75BaWO4/ 0.25CaWO4) nanocomposite is very good efficient thermoelectric power devices at higher temperature application.
Graphic abstract
中文翻译：
BaWO4/CaWO4 纳米复合材料的增强的电和热电功率特性
粉末状xBaWO 4 /(1 - x)CaWO 4其中( x = 0,0.25,0.5,0.75,1) 纳米复合材料是在室温下通过共沉淀法合成的。我们正在报告纳米复合材料在室温 (RT) 下的直流和交流电导率和介电性能。结构表征和 HRTEM 图像证实了纳米复合材料的界面形成。纳米复合材料研究的电流密度-电场（即 J-E）特性揭示了优异的压敏电阻行为。在室温 (RT) 下，在 20 Hz–3 MHz 的频率下测量介电特性。发现 C2 的介电常数更高 (0.5BaWO 4 /0.5CaWO 4) 纳米复合材料与单相相比，原子比 (Ba/Ca) 最大，具有最佳值“ x ”。由 Jonscher 幂律计算的 C2 (0.5BaWO 4 /0.5CaWO 4 ) 纳米复合材料的直流电导率 (σ dc )分别高于单相。对于 C2 (0.5BaWO 4 /0.5CaWO 4 ) 纳米复合材料，也观察到了增强的 AC 电导率。这些增强的 C2 (0.5BaWO 4 /0.5CaWO 4) 纳米复合材料是由于界面处的空间电荷层 (SCL) 形成。详细解释了所有纳米复合材料的传导模型。对纳米复合材料的热电势研究导致赛贝克系数 ( S ) 显示从负值到正值的转变，并在室温 (RT) 下确认了n型半导体。与其他纳米复合材料相比，C3 (0.75BaWO 4 /0.25CaWO 4 ) 纳米复合材料具有更高的功率因数。这种 C2 (0.5BaWO 4 /0.5CaWO 4 ) 纳米复合材料由于其增强的光学和电学性能，可以被认为是一种高效的多功能纳米复合材料，而 C3 (0.75BaWO 4/ 0.25CaWO 4 ) 纳米复合材料是在较高温度下应用的非常好的高效热电功率器件。
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