【摘要】 BiMnO₃因其铁磁性和铁电性共存的可能性倍受关注。然而，经过热处理后BiMnO₃纳米颗粒成分的变化过程尚不清楚。本文选用共沉淀法合成BiMnO₃纳米颗粒，将制备好的纳米颗粒在空气中以不同温度（300～600℃）热处理20 min。利用透射电子显微镜（TEM）、X射线衍射仪（XRD）以及X射线光电子能谱（XPS）系统地研究了BiMnO₃纳米颗粒的成分与晶体结构。TEM结果说明随着热处理温度的升高，BiMnO₃纳米颗粒尺寸逐渐增大。XRD谱显示当热处理温度高于500℃时，晶体结构由原来的单斜相转变为Pnma正交对称相。XPS结果证明氧缺陷会随温度的升高而减少。除此之外，XRD和XPS结果均说明，热处理温度达到600℃时BiMnO₃纳米颗粒会在空气中分解出Bi₂O₃。该研究结果有助于理解热处理对BiMnO₃纳米颗粒成分变化的影响。更多还原

【Abstract】 BiMnO₃ has attracted plenty of attention due to the coexistence of ferromagnetism and ferroelectricity properties simultaneously. However, the composition evolution of BiMnO₃ nanoparticles with heating treatment is not clear. Here, the co-precipitation method was adopted to synthesize BiMnO₃ nanoparticles at moderate temperature to investigate the heating treatment induced surface composition evolution. The as-prepared nanoparticles were heated at different temperatures from 300 ℃ to 600 ℃ in the air for 20 min. The influence of heating temperature on crystalline structure and composition was systematically studied using transmission electron microscope（TEM）, X-ray diffraction（XRD）, and X-ray photoelectron spectroscopy（XPS）, respectively. The TEM images demonstrate that the diameter of BiMnO₃ nanoparticles increases gradually as increasing heating temperature. The XRD results indicate that the structure of BiMnO₃ nanoparticles changes from monoclinic to orthorhombic Pnma symmetry phase when the heating temperature is above 500 ℃. The XPS result suggests that the oxygen defects decrease as increasing heating temperature. Besides that, both XRD and XPS results affirm that BiMnO₃ nanoparticles begin to decompose, presenting the unstable property of BiMnO₃ nanoparticles in the air at a temperature above 600 ℃. The results are valuable in understanding the evolution of the composition of BiMnO₃ nanoparticles with heating treatment.更多还原