Synthsis And Study Of Magnetic Properties Of Fe₃O₄Doped La³⁺ And CoFe₂O₄Nanoparticles

Magnetic nanomaterials are function materials which are concentration of magnetic materials and nanomaterials, having both magnetic properties of magnetic materials and special chemical and physical properties of nanomaterials. So, magnetic nanomaterials own special magnetic properties,such as high coercive force,superparamagnetism,low Curie temperature,single magnetic domain and so on. Therefore magnetic nanomaterials have become a hot area of research in recent years. Spinel type ferrite have been used in wide areas such as biomedicine,magnetic storage materials,catalytic agent and so on for their good electromagnetic properties and it is a kind of important magnetic nanomaterials.In this paper,the Fe3O4nanoparticles doped La3+and CoFe2O4nanoparticles have been prepared by sol-gel method respectively The structure and phase、the size and the shape、the magnetic properties of the nanoparticals prepared were analysised and studied by X-ray diffraction(XRD)、Scanning electron microscope(SEM)、 Physical property measurement system(PPMS),respectively. And parameters which influence chemical and physical properties of samples have been studied in order to find the experimental basis for the next work.The following results are obtained through the study and analyzing:(1) The preparation of the FesO4nanoparticles doped La3+:the prepared cycle of the Fe3O4nanoparticles doped La3+is shortened highly when using spontaneous combustion sol-gel method; the morphology of the nanoparticles is the best which are prepared thongh water bathing5h at80℃,calcinating5h at800℃。(2) The preparation of the CoFe2O4nanoparticles:CoFe2O4nanoparticles whose size is uniform have been synthtized though sol-gel method using polyving akohol(PVA) and polyethylene glycol(PEG) as dispersants and gelatas; And the size of nanoparticles prepared using PEG and PVA as dispersants and gelatas is20～40nm and～100nm respectively; the remanence ratio and the saturation magnetism of the nanoparticals using PEG is0.42and143.11emu/g respectively,it is mostly because that Co2+cations have been redistributed in A site and B site; and when the amount of PEG is different,the morphology and the magnetic properties is different,the morphology and the magnetic properties is the best when the amount of PEG is4g.