Saidi A, Mabrouki A, Dhahri R, Dhahri E, Khirouni K, Costa B F O
Laboratoire de Physique Appliquée, Faculté des Sciences, Université de Sfax, Tunisia.
Laboratoire de Physique des Matériaux et des Nanomatériaux Appliquée à l'Environnement, Faculté des Sciences, Université de Gabes, Tunisia.
Heliyon. 2023 Jul 29;9(8):e18780. doi: 10.1016/j.heliyon.2023.e18780. eCollection 2023 Aug.
This article explores the impact of co-doping BaTiO ceramics with Ca and Y using solid-state reactions to improve its dielectric constant and decrease losses. The oxide BCTYO (BaCaTiYO) exhibits a tetragonal crystal structure, characterized by a space group of 4. By examining the behavior of the doped BaTiO sample and performing simulations, researchers can better understand the underlying mechanisms and optimize material properties for specific applications. DFT study shows a semiconductor behavior with an indirect gap (E = 2.5 eV). The partial DOS proves that the hybridization between the orbitals Ti 3d, Y 3d, and O 2p is responsible for the band gap and the hopping processes. The analysis of conductivity curves provides evidence for the semiconductor characteristics of the material under investigation. By determining the activation energy (E) through analyzing Ln(f) and conductivity as a function of 1000/T, the interconnection between conduction and relaxation phenomena is demonstrated. The study of the real part of the dielectric permittivity (ε') shows a transition at T = 380 K. The obtained results are promising and indicate that the studied material has the potential for various electronic applications (energy storage and diode fabrication …). Moreover, the thermal, electrical, and thermoelectric characteristics were examined utilizing the semi-classical Boltzmann theory. The findings revealed an intriguing result, suggesting that BaCaTiYO holds promise as a potential candidate for application in thermoelectric devices.
本文探讨了通过固态反应共掺杂钙（Ca）和钇（Y）的钛酸钡（BaTiO）陶瓷，以提高其介电常数并降低损耗。氧化物BCTYO（BaCaTiYO）呈现四方晶体结构，其空间群为4。通过研究掺杂的钛酸钡样品的行为并进行模拟，研究人员能够更好地理解其潜在机制，并针对特定应用优化材料性能。密度泛函理论（DFT）研究表明该材料具有间接带隙（E = 2.5 eV）的半导体行为。部分态密度证明，Ti 3d、Y 3d和O 2p轨道之间的杂化作用导致了带隙和跳跃过程。电导率曲线分析为所研究材料的半导体特性提供了证据。通过分析Ln(f)和电导率随1000/T的变化来确定活化能（E），证明了传导和弛豫现象之间的相互联系。对介电常数实部（ε'）的研究表明，在T = 380 K时发生了转变。所得结果很有前景，表明所研究的材料具有用于各种电子应用（能量存储和二极管制造等）的潜力。此外，利用半经典玻尔兹曼理论研究了其热、电和热电特性。研究结果揭示了一个有趣的结果，表明BaCaTiYO有望成为热电装置应用的潜在候选材料。
