掺杂Mg对纳米CoFe2O4/SiO2复合薄膜结构和磁性的影响

采用溶胶-凝胶旋涂法制备了纳米Co_1-xMg _xFe₂O₄/SiO₂(x = 0, 0.2, 0.4, 0.6, 0.8) 复合薄膜。利用XRD、SEM、原子力显微镜、振动样品磁强计对薄膜的结构、形貌和磁性进行了分析, 研究了Mg²⁺含量对样品结构和磁性的影响。结果表明, 样品中Co_1-xMg _xFe₂O₄具有尖晶石结构, 晶粒尺寸在38~46 nm之间。随着Mg²⁺含量的增加, Co_1-xMg _xFe₂O₄的晶格常数减小, 样品的饱和磁化强度减小, 矫顽力先增大后减小。样品Co_0.4Mg_0.6Fe₂O₄/SiO₂垂直和平行膜面的矫顽力分别为350.7 kA·m^-1和279.4 kA·m^-1, 剩磁比分别为67.2%和53.9%, Co_1-xMg _xFe₂O₄/SiO₂复合薄膜具有较明显的垂直磁各向异性。

Effect of Mg-doping on the structural and magnetic properties of CoFe_2O_4/SiO_2 nanocomposite films

Co 1-x Mg x Fe 2 O 4 /SiO 2 (x=0, 0.2, 0.4, 0.6, 0.8) nanocomposite films were prepared by sol-gel spin-coating process. The effect of the addition of Mg 2+ with various content on the structure and magnetic properties of the samples was investigated. The structure, morphology and magnetic properties of the films had been studied through XRD, SEM, atomic force microscopy (AFM) and vibrating sample magnetometer (VSM). The results show that the Co 1-x Mg x Fe 2 O 4 presents spinel structure in composite films with grain size of about 38-46 nm. As the content of Mg increases, the lattice constant of Co 1-x Mg x Fe 2 O 4 decreases, the saturation magnetization of sample films decreases also, while the coercivity first increases and then decreases. The value of coercivity and remanence ratio in the direction of parallel to the plane for Co 0.4 Mg 0.6 Fe 2 O 4 /SiO 2 sample film is 279.4 kA/m and 53.9%, respectively, while the corresponding value in the direction of perpendicular to the plane is 350.7 kA/m and 67.2%. The samples display distinct perpendicular magnetic anisotropy.