采用乙二胺四乙酸杂化溶胶法制备了不同晶粒尺寸的纯相BiFeO_3纳米颗粒,并利用X射线衍射仪、扫描电镜、超导量子干涉仪和Mossbauer谱系统研究了其结构、形貌以及磁性能.结果表明:BiFeO_3纳米颗粒具有明显的弱铁磁性,并呈现强烈的尺寸依赖特性;这种弱铁磁性主要源于纳米材料的尺寸限制效应,而非杂质相或Fe~(2+)的存在所致. Pure phase BiFeO_3 nanoparticles with different grain sizes were prepared by ethylenediaminetetraacetic acid hybrid sol-gel method. Their structures, morphologies and morphology were characterized by X-ray diffraction, scanning electron microscopy, superconducting quantum interference spectroscopy and Mossbauer spectroscopy The results show that the BiFeO_3 nanoparticles have obvious weak ferromagnetism and exhibit strong size dependence. The weak magnetic properties of FeFe2_3 mainly originate from the size limitation of nanomaterials, Due to the existence of.