二元CoFe2O4-p-MgFe2O4磁性液体的制备及磁化特性研究

采用化学共沉淀法制备了CoFe2O4强磁性纳米微粒和p-MgFe2O4(Mg(OH)2与Fe(OH)3的混合物)弱磁性纳米微粒.并按体积比为1:1将CoFe2O4磁性液体、p-MgFe2O4顺磁磁性液体混合,得到二元CoFe2O4-p-Mg-Fe2O4磁性液体.实验结果表明混合磁性液体的磁化强度不能简单等于两种单一磁性液体磁化强度的叠加.在CoFe2O4磁性液体中,其磁性微粒在无场时会自发组装形成对磁化强度无贡献的闭合环状团聚体结构.二元磁性液体磁化时,这种CoFe2O4微粒环可能部分破裂.根据偶极子相互作用能判断CoFe2O4体系与p-MgFe2O4体系无相互作用,因此可根据单元磁性液体的磁化性质为基础来分析二元磁性液体的磁化性质.

Abstract：

Strong magnetic CoFe2O4 nanoparticles and weak magnetic p-MgFe2O4 (mixture of hydroxide Mg(OH)2 and Fe(OH)3) nanoparticles are produced by the chemical co-precipitation technology. Binary ferrofluids of CoFe2O4-p-MgFe2O4 are obtained by mixing CoFe2O4 ferrofluids and p-MgFe2O4 paramagnetic fluids in a ratio of 1: 1 (v/v). The experimental results indicate that the magnetization of the binary ferrofluid is not simple summation of the two single magnetic fluids. Without external magnetic field,some particles can self-assemble into aggregates of closed ring-like structures, which make no contribution to the magnetization for the CoFe2O4 ferofluid. In the magnetization process of the binary ferrofluid, the closed ring-like structure can partially break. Based on the interaction between two dipoles, it can be judged that there is no magnetic interaction between the CoFe2O4 magnetic system and the p-MgFe2O4 magnetic system. Therefore, the magnetization behavior of the binary ferrofluids can be analyzed based on the single magnetic fluids.

Preparation and Magnetization Behaviors of CoFe2O4-p-MgFe2O4 Binary Ferrofluids