【摘要】 采用溶胶凝胶自组装法合成了钴铁氧体和Dy掺杂的钴铁氧体磁性纳米晶铁氧体。由热重-差热分析可知,尖晶石结构的CoFe_2-xDy_xO₄纳米晶铁氧体在400℃左右时候形成。用X射线衍射对样晶进行了结构表征,由其结果确定了所有样品的烧结温度为800℃,Dy的掺杂导致了钴铁氧体纳米颗粒的平均晶粒尺寸变小,采用振动样品磁强计表征了样品的磁性能。结果表明,随着Dy掺杂量的增加,样品的矫顽力明显增加,而比饱和磁化强度下降。分析认为超交换作用和电子自旋-轨道耦合对CoFe_2-xDy_xO₄样品的矫顽力起了重要作用。更多还原

【Abstract】 CoFe₂O₄ and Dy-doped CoFe₂O₄(CoFe_2-xDy_xO₄,x=0,0.025,0.05 and 0.075) magnetic nanocrystalline ferrites have been synthesized by sol-gel and self-combustion method.The spinel phase structure of nanocrystalline CoFe_2-xDy_xO₄ is formed at about400 ℃ confirmed by Thermal Gravity Analysis（TGA） and Differential Scanning Calorimetry（DSC）.According to the results from X-ray diffraction（XRD）,all samples are sintered at 800 ℃,and the average size of Dy-doped samples is smaller than that of pure CoFe₂O₄.Furthermore,the magnetic properties of CoFe_2-xDy_xO₄ were discussed by vibrating sample magnetometer（VSM）,indicating an obvious increase of coercivity and decrease of saturation magnetization with the Dy-doped content.We think that superexchange interactions and spin-orbital coupling should play an important role on the coercivity of CoFe_2-xDy_xO₄.更多还原