Chemical Synthesis, Self-assembly, Magnetic Properties Of FePt&Fe₃O₄Nanoparticles And Related Composite Materials

Nano-magnetic materials were widely used in magnetic recording materials, nano permanent magnet materials propertiesabsorbing materials, biomedical, chemical catalysis and other fields, because of their unique physical and chemical properties. Along with the deepening of the research on magnetic nanomaterials, people expect the emergence of higher performance magnetic materials. This topic based on the synthesis of Face-centered tetragonal(fct) FePt nanocubes and Fe3O4nanocubes, take the preparation of FePt/Fe3O4magnetic nanoparticles membrane as the main content, take the enhancing of magnetic properties as the main purpose.The main researchs of our work include the following aspects:(1) The goal of our topic is to prepared the FePt super-high density magnetic recording medium with high coercive force and high remanence.Using the method of high temperature liquid phase to synthesize a10nm fept cubic nanoparticles with uniform size, here we have creatively modified the synthesis by employing Mo(CO)6as the inducing agent. As-synthesized FePt nanocubes are lOnm and be assembled into arrays, thermal annealing of the FePt nanocube superlattice induces FePt structure transformation from fcc to fct phase. Thus, this work demonstrates progress in the development of magnetic recording media based on FePt nanoparticles.(2) We adopt the "bottom-up" self-assembly technique to prepare a series of FePt/Fe3O4dual membranes, and use10nm FePt and10nm Fe3O4to construct the hard and soft magnetic exchange coupling double magnetic nanoparticle arrays, the recent studies has found that through the soft and hard magnetic nanoparticles, the exchange coupling effect between medium can improve the residual magnetism. It provides a new way to develop the preparation of nanometer coupling magnet.(3) This dissertation is devoted to the design and controlled synthesis of exchange coupling nanocomposite magnets, such as heterogeneous FePt-Fe3O4nanoparticles, core-shell FePt@Fe3O4nanowires and nanospheres, PtCo nanoparticles. It’s beneficial to the develop of new nano-magnetic materials.