Abstract Bismuth Ferrite (BiFeO3) is one such materials which has shown very promising multiferroic and excellent optical properties. In this paper, we report effect of annealing temperature on the structural, morphological and optical properties of BiFeO3 nanoparticles synthesised through sol-gel auto-combustion method. Nanoparticles prepared were calcined at three different temperatures, 400 °C, 500 °C and 600 °C, and named as BFO1, BFO2 and BFO3, respectively. X-ray diffraction confirmed the rhombohedral structure with R3c space group as a primary phase. However, a secondary phase Bi2Fe4O9 was also observed which decreases with increasing temperature. The crystallite sizes were found to increase with increasing temperature with BFO2 as anomaly. Field emission scanning electron microscopy (FESEM) shows clear grain formation for all the samples. TEM micrographs and SAED patterns show crystalline grains with rhombohedral structure. All the functional groups observed in the Fourier infrared spectroscopy (FTIR) measurement are indexed. The FTIR spectra shows presence of two prominent vibrational modes in the wave number range 447 and 560 cm-1 corresponding to the stretching of Fe-O bonds. Raman analysis shows presence of a peak at ~527 cm-1 for (BFO3) which was absent in other two samples. Also, the intensity of the A1-1 mode was found stronger than that of A1-2 mode in all the samples which confirmed the stability of the structure, except for BFO1.

中文翻译：

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煅烧温度对铁氧体铋纳米颗粒结构和形貌的影响

摘要 铁氧体铋（BiFeO3）就是这样一种材料，它显示出非常有前途的多铁性和优异的光学性能。在本文中，我们报告了退火温度对通过溶胶-凝胶自燃法合成的 BiFeO3 纳米粒子的结构、形态和光学性质的影响。制备的纳米颗粒在 400°C、500°C 和 600°C 三种不同温度下煅烧，分别命名为 BFO1、BFO2 和 BFO3。X 射线衍射证实了以 R3c 空间群为主相的菱形结构。然而，也观察到随温度升高而减少的第二相 Bi2Fe4O9。发现微晶尺寸随着温度升高而增加，BFO2 作为异常。场发射扫描电子显微镜 (FESEM) 显示所有样品均形成清晰的晶粒。TEM 显微照片和 SAED 图案显示具有菱形结构的晶粒。在傅里叶红外光谱 (FTIR) 测量中观察到的所有官能团都被编入索引。FTIR 光谱显示在波数范围 447 和 560 cm-1 中存在两种突出的振动模式，对应于 Fe-O 键的拉伸。拉曼分析显示 (BFO3) 在 ~527 cm-1 处存在一个峰，而其他两个样品中不存在该峰。此外，在确认结构稳定性的所有样品中，除 BFO1 外，A1-1 模式的强度比 A1-2 模式强。FTIR 光谱显示在波数范围 447 和 560 cm-1 中存在两种突出的振动模式，对应于 Fe-O 键的拉伸。拉曼分析显示 (BFO3) 在 ~527 cm-1 处存在一个峰，而其他两个样品中不存在该峰。此外，在证实结构稳定性的所有样品中，除 BFO1 外，A1-1 模式的强度比 A1-2 模式强。FTIR 光谱显示在波数范围 447 和 560 cm-1 中存在两种突出的振动模式，对应于 Fe-O 键的拉伸。拉曼分析显示 (BFO3) 在 ~527 cm-1 处存在一个峰，而其他两个样品中不存在该峰。此外，在确认结构稳定性的所有样品中，除 BFO1 外，A1-1 模式的强度比 A1-2 模式强。