Abstract Ca and Mn co-substituted Bi1-xCaxFe1-xMnxO3 (x = 0 and 0.10) polycrystalline ceramic samples were prepared using conventional solid state reaction method. The structural, morphological, vibrational, Raman, optical and electrical properties of co-doped and pristine compounds were carried out. The formation of the compounds was analyzed using RT (room temperature) X-ray diffraction patterns. These diffraction patterns were further refined using Rietveld refinement via FULLPROF software and were found to fit in rhombohedral crystalline structure with space group R3c. The observed and calculated diffraction patterns are in good agreement with each other. The average crystallite size has been calculated using Scherrer formula. The same has also been calculated using W–H plot along with the strain developed in the lattice due to substitution. The average crystallite size has further been used to calculate the dislocation density and number of crystallites in a given pellet of area 38.56 mm2 and 63.92 mm2 for Bi1-xCaxFe1-xMnxO3 with x = 0 and 0.10 respectively. The 2D and 3D surface morphology of prepared samples were analyzed using Atomic Force Microscopy (AFM). The average roughness and average crystallite size was also calculated using SPIP software. FTIR spectra in transmittance mode give a brief idea of Vibrational modes around Fe–O–Fe stretching bonds. The appearance of active modes in Raman spectroscopy at RT also confirmed the rhombohedral structure with R3c space group. The Optical property of the materials has been studied using UV-VIS-NIR spectroscopy. The optical energy band gap of the pristine compound was found to be 2.04eV which is comparable to that of the literature value but the co-doping of Ca and Mn in pristine compound lowered (1.86eV) the optical band gap. The dc conductivity was analyzed and the activation energies were calculated using Arrhenius relation. The Current-Voltage (I–V) characteristic as a function of temperature was also analyzed which shows the semiconducting behaviour of the compounds. The results are discussed in detail.

中文翻译：

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Ca/Mn 共掺杂 BiFeO3 的 Rietveld 细化、形态、振动、拉曼、光学和电学性质

摘要 采用常规固相反应法制备了Ca和Mn共取代的Bi1-xCaxFe1-xMnxO3（x=0和0.10）多晶陶瓷样品。进行了共掺杂和原始化合物的结构、形态、振动、拉曼、光学和电学性质。使用RT（室温）X-射线衍射图分析化合物的形成。这些衍射图通过 FULLPROF 软件使用 Rietveld 细化进一步细化，发现它们符合空间群为 R3c 的菱面体晶体结构。观察到的和计算出的衍射图彼此非常吻合。使用 Scherrer 公式计算平均晶粒尺寸。使用 W-H 图以及由于取代而在晶格中产生的应变也可以计算出相同的结果。对于 Bi1-xCaxFe1-xMnxO3，x 分别为 0 和 0.10，平均微晶尺寸进一步用于计算面积为 38.56 mm2 和 63.92 mm2 的给定丸粒中的位错密度和微晶数量。使用原子力显微镜 (AFM) 分析制备的样品的 2D 和 3D 表面形态。平均粗糙度和平均微晶尺寸也使用 SPIP 软件计算。透射模式下的 FTIR 光谱简要介绍了 Fe-O-Fe 拉伸键周围的振动模式。室温拉曼光谱中活性模式的出现也证实了具有 R3c 空间群的菱形结构。已经使用UV-VIS-NIR光谱研究了材料的光学性质。发现原始化合物的光能带隙为 2。04eV 与文献值相当，但原始化合物中 Ca 和 Mn 的共掺杂降低了 (1.86eV) 的光学带隙。分析直流电导率并使用阿伦尼乌斯关系计算活化能。还分析了作为温度函数的电流-电压 (I-V) 特性，这显示了化合物的半导体行为。结果进行了详细讨论。