Mn_(0.6)Zn_(0.4)Fe_2O_4磁性亚微球的可控合成及磁性能

Controlled Fabrication of Mn_(0.6)Zn_(0.4)Fe_2O_4 Magnetic Submicrospheres and Their Magnetic Properties

采用溶剂热法制备了单分散Mn0.6Zn0.4Fe2O4磁性亚微米球,研究了反应工艺参数对磁性亚微米球结构形貌、直径和静磁性能的影响规律.研究发现,随着反应时间的延长,体系中的金属离子首先水解沉淀,形成羟基氧化铁及Mn,Zn氢氧化物,然后脱水转化为Mn0.6Zn0.4Fe2O4球形纳米粒子,这些纳米粒子发生团聚,形成结构疏松、大小不均匀的亚微米粒子,最后通过Ostwald熟化过程,形成致密的单分散亚微米球.降低反应溶液的pH值、增加乙二醇或聚乙二醇的用量,均会使亚微球的直径增大,并可在150～500 nm范围内调控微球的粒径;但组成磁性亚微球的纳米粒子的粒径逐渐减小,产物的饱和磁化强度增大,矫顽力和剩磁减小.

Monodispersed manganese-zinc ferrite（Mn0.6Zn0.4Fe2O4） submicrospheres were synthesized by a simple solvothermal method.The influences of reaction parameters on the structure,morphology,diameter and magnetic properties of the Mn0.6Zn0.4Fe2O4 submicrospheres were investigated.The results showed that metal ions were first hydrolyzed to form ferric hydroxide,manganic hydroxide and zinc hydroxide,which then dehydrated to form Mn0.6Zn0.4Fe2O4 nanoparticles.These Mn0.6Zn0.4Fe2O4 nanoparticles first agglomerated to produce homogeneous submicrospheres with loose structure,and finally evolved into compact monodispersed submicrospheres through Ostwald ripening.Increasing the amount of ethylene glycol or polyethylene glycol or decreasing pH value,the diameter of the submicrospheres could be controlled in a range of 150—500 nm,while the size of nanoparticle which composed the submicrospheres decreased,consequently,saturation magnetization increased,remanence and coercivity decreased.