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Co_xFe_(3-x)O_4晶体属尖晶石型结构,具有良好的磁光效应及化学稳定性。在尖晶石型铁氧体中,金属离子存在着A-A、B-B和A-B晶位间超交换作用,其中以A-B间的超交换作用最强。超交换作用引起不同次晶格的磁矩反向排列,而铁氧体的亚铁磁性则来源于晶格中A、B位上未抵消的反向磁矩。尖晶石型单一铁氧体MFe_2O_4晶格中离子分布通常为Fe_xM_(1-x)[M_xFe_(2-x)]O_4。在三价铁盐和二价钴盐混合水溶液中滴加碱液可制备CoFe_2O纳米晶。本文用改进的化学共沉淀法,以不同摩尔浓度的Co(Ⅱ)和Fe(Ⅱ)合成Co_xFe_(3-x)O_4纳米晶系列样品,考察了样品组成与其磁性的关系。
Co_xFe_ (3-x) O_4 crystal belongs to spinel structure with good magneto-optical effect and chemical stability. In the spinel ferrite, the metal ions exist between the A-A, B-B and A-B crystalline sites of the super-exchange effect, in which the A-B between the super-exchange effect of the strongest. The super-exchange effect causes the magnetic moments of different sub-lattices to be reversed, while the ferrimagnetism of the ferrite is derived from the un-canceled reverse magnetic moment in the A and B positions of the crystal lattice. The ion distribution in the spinel single ferrite MFe_2O_4 lattice is usually Fe_xM_ (1-x) [M_xFe_ (2-x)] O_4. CoFe 2 O nanocrystals can be prepared by adding alkali solution into ferric salt and divalent cobalt salt mixed aqueous solution. In this paper, Co_xFe_ (3-x) O_4 nanocrystals were synthesized by the chemical co-precipitation method with different molar concentrations of Co (Ⅱ) and Fe (Ⅱ). The relationship between the composition and the magnetic properties was investigated.