Preparation of Magnetic Nanoparticles via a Chemically Induced Transition: Presence/Absence of Magnetic Transition on the Treatment Solution Used

The dependence of magnetic transition on the treatment solution used in the preparation of magnetic nanoparticles was investigated using as-prepared products from paramagnetic feooh/mg(oh)via a chemically induced transition. treatment using fecland cucl solutions led to a product that showed no magnetic transition,whereas the product after treatment with fesoor feclsolutions showed ferromagnetism. experiments revealed that the magnetism was caused by the ferrimagnetic γ-fephase in the nanoparticles,which had a coating of ferric compound. this observation suggests that fe2+ in the treatment solution underwent oxidation to fe3+,thereby inducing the magnetic transition. the magnetic nanoparticles prepared via treatment with an fesosolution contained a larger amount of the nonmagnetic phase. this resulted in weaker magnetization even though these nanoparticles were larger than those prepared by treatment with an feclsolution. the magnetic transition of the precursor (feooh/mg(oh) was dependent upon treatment solutions and was essentially induced by the oxidation of fe2+ and simultaneous dehydration of feooh phase. the transition was independent of the acid radical ions in the treatment solution,but the coating on the magnetic crystallites varied with changes in the acid radical ion. © 2016 yanshuang chen et al.