纳米Co_(1-x)Zn_xFe_2O_4/SiO_2复合材料的结构和磁性

为了研究Zn2+含量对CoZn铁氧体结构和磁性的影响,以正硅酸乙酯和硝酸盐为原料,用溶胶-凝胶法制备了纳米Co1-xZnxFe2O4/Si O2(0≤x≤1)复合材料。利用XRD、TEM、VSM和M ssbauer效应分析了样品的结构、形貌和磁性。结果表明,经900℃热处理后,Co1-xZnxFe2O4/Si O2复合材料中Co1-xZnxFe2O4为晶粒分布均匀的尖晶石铁氧体结构。Zn2+替代Co2+后引起Co1-xZnxFe2O4晶格膨胀。随Zn2+含量的增加,样品的矫顽力减小,而比饱和磁化强度先增大后减小,样品从磁有序状态转变为顺磁状态。Zn2+的掺杂对Fe3+核处的s电子密度有较大的影响,对尖晶石结构对称性影响较小。

Structure and magnetic properties of nano Co1-xZnxFe2O4/SiO2 composites

Nano Co1-xZnxFe2O4/SiO2 (0≤x≤1) composites were prepared by sol-gel method using teterathylor- thodilicate and nitrates as precursor in order to investigate the effect of Zn2+ content on the structure and magnetic properties of composites. The structure, morphology and magnetic properties of the composites were investigated by XRD, TEM, VSM and Mssbauer effect. The results show that Co1-xZnxFe2O4 grains distribute uniformly in nano Co1-xZnxFe2O4/SiO2 composites and present cubic spine structure. The unit cell of Co1-xZnxFe2O4 expands after Zn2+ substituting Co2+. With the increasing of Zn2+ content, the coercivity of the composites decreases, and the value of saturation magnetization increases firstly then decreases, while the composites transform from magnetic order state into paramagnetic state. The doping of Zn2+ has more effect on the density of s-electron around Fe3+ nucleus, less effect on structural symmetry.