Valenzuela-Carrillo M I, Pérez-Labra M, Barrientos-Hernández F R, Romero-Serrano J A, Reyes-Pérez M, Cruz-Ramírez A, Flores-Guerrero M U, Juárez-Tapia J C
Academic Area of Earth Sciences and Materials. Autonomous University of Hidalgo State. Road Pachuca- Tulancingo Km 4.5 Mineral de la Reforma Zip Code 42184, Hidalgo Mexico.
Instituto Politécnico Nacional, ESIQIE, Metallurgy and Materials Department, Zacatenco, Zip Code 07738, Ciudad de México, México.
Heliyon. 2024 Sep 26;10(19):e38463. doi: 10.1016/j.heliyon.2024.e38463. eCollection 2024 Oct 15.
In this study, the synthesis and structural evolution of pure BaTiO and BaTiO co-doped with La and Bi, produced using the ball milling method and heat treatment, were analyzed. The starting materials included chemically pure precursor powders of BaCO, TiO, LaO and BiO. Stoichiometric calculations were performed using the BaLaTiBiO mechanism with concentrations x = 0.0, 0.0025, 0.0045, 0.006, 0.01, and 0.05 (mol %). The structural and morphological evolution of the samples was characterized by x-ray diffraction (XRD), Rietveld refinement, and high-resolution scanning electron microscopy (HRSEM-EDS). XRD and Rietveld refinement results indicated a tetragonal ferroelectric phase for samples with x ≤ 0.006. As doping levels increased, a peak disappearance was observed, corresponding to a phase transformation from tetragonal to cubic at x = 0.01. Additionally, a cubic secondary phase, BaBiO₃, was detected at x = 0.05, indicating that the maximum solubility of La³⁺ and Bi³⁺ ions in BaTiO was exceeded at this concentration. The concentration x = 0.0025 was found to exhibit the maximum tetragonality among the samples studied, with a value of 1.0087, greater than the tetragonality for pure BaTiO, 1.0083. The HRSEM-EDS analysis revealed that for samples with x ≤ 0.006, the microstructure consisted of faceted shape grains with mean grain size in the range of 362.5 nm-488.3 nm. Punctual microanalysis and elemental distribution mapping of the doped samples showed that the grains were composed of Ba, Ti, O, Bi, and La, which were homogeneously distributed, confirming the incorporation of the dopant elements into the BaTiO structure.
在本研究中，对采用球磨法和热处理制备的纯BaTiO以及La和Bi共掺杂的BaTiO的合成及结构演变进行了分析。起始原料包括化学纯的BaCO₃、TiO₂、La₂O₃和Bi₂O₃前驱体粉末。使用BaLaTiBiO机制进行化学计量计算，浓度x = 0.0、0.0025、0.0045、0.006、0.01和0.05（摩尔%）。通过X射线衍射（XRD）、Rietveld精修和高分辨率扫描电子显微镜（HRSEM-EDS）对样品的结构和形态演变进行了表征。XRD和Rietveld精修结果表明，x≤0.006的样品为四方铁电相。随着掺杂水平的增加，观察到一个峰消失，对应于x = 0.01时从四方相到立方相的相变。此外，在x = 0.05时检测到立方次生相BaBiO₃，表明在此浓度下La³⁺和Bi³⁺离子在BaTiO中的最大溶解度已被超过。发现在所研究的样品中，浓度x = 0.0025表现出最大的四方度，值为1.0087，大于纯BaTiO的四方度1.0083。HRSEM-EDS分析表明，对于x≤0.006的样品，微观结构由多面体形晶粒组成，平均晶粒尺寸在362.5 nm - 488.3 nm范围内。对掺杂样品的逐点微分析和元素分布图显示，晶粒由Ba、Ti、O、Bi和La组成，它们均匀分布，证实了掺杂元素已掺入BaTiO结构中。
