Abstract Nanostructured Sr2FeMoO6 double perovskite was synthesized by the sol-gel combustion method. X-ray diffraction results showed that SrMoO4 starts to form at 450 °C, and the formation of single-phase double perovskite with a tetragonal I4/m space group occurs at a relatively low temperature of 750 °C. Rietveld refinement by FullProf software showed the mean crystallite size of 49 nm, and unit cell parameters of a = b = 5.577 A and c = 7.918 A for the synthesized Sr2FeMoO6. Analysis of the FTIR spectra revealed that with mechanical activation process, the peak corresponding to the C–O band at 2341 cm−1 vanishes and intensity of carboxyl group (1445 cm−1) and nitrate ions band (1396 cm−1) are affected. The presence of the peaks related to the vibration of metal ions bands at octahedral sites at 644 and 831 cm−1 confirms the evolution of Sr2FeMoO6 double perovskite structure. Scanning electron microscope images showed that the Sr2FeMoO6 powder processed at 750 °C in 5%H2/N2 atmosphere has a mean particle size of about 250 nm. It was observed that the saturation magnetization increases to the high value of 18 emu.g−1 in the ordered structure at 800 °C. High Curie temperature of 423 K in the prepared sample makes it a promising candidate for the magnetocaloric applications.

中文翻译：

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Sr2FeMoO6双钙钛矿的低温合成；结构、形态和磁性

摘要 采用溶胶-凝胶燃烧法合成了纳米结构的Sr2FeMoO6双钙钛矿。X 射线衍射结果表明 SrMoO4 在 450°C 开始形成，具有四方 I4/m 空间群的单相双钙钛矿的形成发生在 750°C 的较低温度。FullProf 软件的 Rietveld 细化显示，合成的 Sr2FeMoO6 的平均微晶尺寸为 49 nm，晶胞参数 a = b = 5.577 A 和 c = 7.918 A。FTIR 光谱分析表明，在机械活化过程中，对应于 2341 cm-1 处的 C-O 带的峰消失，羧基（1445 cm-1）和硝酸根离子带（1396 cm-1）的强度受到影响. 与金属离子带在 644 和 831 cm-1 处八面体位置振动相关的峰的存在证实了 Sr2FeMoO6 双钙钛矿结构的演变。扫描电子显微镜图像显示，在 750 °C 和 5% H2/N2 气氛中处理的 Sr2FeMoO6 粉末的平均粒径约为 250 nm。据观察，在 800 °C 时，在有序结构中饱和磁化强度增加到 18 emu.g-1 的高值。制备的样品中 423 K 的高居里温度使其成为磁热应用的有希望的候选者。g-1 在 800 °C 的有序结构中。制备的样品中 423 K 的高居里温度使其成为磁热应用的有希望的候选者。g-1 在 800 °C 的有序结构中。制备的样品中 423 K 的高居里温度使其成为磁热应用的有希望的候选者。