Fe_3O_4纳米粒子的制备与超顺磁性

Preparation and superparamagnetism of Fe_3O_4 nanoparticles

采用红外光谱、X射线衍射、透射电子显微镜和振动样品磁强计对用化学共沉淀法制备出的纳米Fe3O4粒子进行了形貌、结构及磁性能表征。其中,红外和XRD测试结果表明制备出的Fe3O4粒子的物态和晶相结构;透射电子显微镜照片表明制备出的纳米四氧化三铁成球性好,且大部分四氧化三铁粒子的粒径在10nm左右;磁化曲线表明制备出的Fe3O4粒子无剩磁和矫顽力,具有超顺磁性。并且,将制备出的纳米Fe3O4粒子和块状Fe3O4的磁性能进行对比,探讨了Fe3O4由块状的亚铁磁性向纳米级的超顺磁性转变的原因。

Fe3O4 nanoparticles were prepared by chemical co-precipitation,and characterized by IR, XRD,TEM and VSM（vibrating sample magnetometer）. XRD and IR results revealed that the state of matter and crystal structure of the as-deposited Fe3O4 particles. TEM showed that the size of the prepared product is about 10nm. Magnetization curves indicated that the as-deposited Fe304 particles without remanent magnetization（Mr） and coercivity（Hc）, and with superparamagnetism. The magnetism of Fe3O4 nanoparticles and block Fe3O4 were compared,and the transformation from the sub-ferromagnetism to the superparamagnetism were interpreted.