水热法制备Co掺杂CeO2纳米晶的微观形貌及磁学性能研究

以Ce(NO3)3·6H2O和Co(NO3)3·6H2O为原料,Na3PO4·12H2O为沉淀剂,用水热法制备了不同浓度Co掺杂的CeO2纳米晶.利用XRD、Raman、SEM、PPMS等测试手段研究纳米晶的晶体结构、微观形貌和磁学性能.XRD和Raman研究结果表明,不同浓度Co掺杂的CeO2纳米晶仍保持纯CeO2的立方莹石结构.没有出现Co以及Co氧化物的特征峰,说明Co掺杂替换了CeO2中的Ce晶格位.XRD的特征峰未出现明显的平移,Co掺杂导致CeO2的晶格畸变也不明显.SEM研究发现纳米晶的形状都是棱长约为600～800 nm的八面体,Co掺杂CeO2纳米晶的微观形貌与Co掺杂浓度存在明显关系,随着Co掺杂浓度的增加,八面体的棱从清晰变为模糊,各个面从光滑变为粗糙.PPMS测量表明所有样品都表现出室温铁磁性,随着Co掺杂浓度的增加,饱和磁化强度先增加后减小,5;Co掺杂CeO2纳米晶具有最大的饱和磁化强度.不同Co掺杂浓度导致纳米晶的磁性有了明显的变化,可见通过改变Co掺杂浓度可以调制纳米晶的室温铁磁性能.

Microscopic Morphology and Magnetic Properties of Co Doped CeO2 Nanocrystals Prepared by Hydrothermal Method

Co doped CeO 2 nanocrystals with different Co concentrations were prepared by hydrothermal method .The crystal structure , microscopic morphology and magnetic properties of these nanocrystals were investigated by XRD, Raman, SEM and PPMS.The results of XRD and Raman indicate that the CeO2 nanocrystals with different Co concentrations are cubic fluorite structure .No Co and Co oxides peaks were found, which indicates that Co doping replaced the Ce in CeO 2 lattice.The characteristic peaks of XRD show no obvious translation , so the lattice distortion of CeO 2 is not obvious due to Co doping .SEM images show that the nanocrystals are octahedrites with an edge length of about 600-800 nm.Microscopic morphology of Co doped CeO 2 nanocrystals has obvious relationship with the Co doping concentration . With the increase of Co doping concentration , the edge of octahedrites become from clear to fuzzy , and the surface from smooth to rough .PPMS measurements show that all the samples exhibit room temperature ferromagnetism .With the increase of Co doping concentration , the saturation magnetization increases first and then decreases , and the 5;Co doped CeO 2 nanocrystals has the maximum saturation magnetization .The magnetic properties of nanocrystals are obviously changed by different Co doping concentration .The room temperature ferromagnetism of nanocrystals can be modulated by changing the concentration of Co .