Research On The Preparation And Magnetic Properties Of Low-dimension Nanostructure Materials Of FePt

Low dimensional FePt nanomaterials with L10structure have excellent magnetic properties and catalytic performances. Therefore, the FePt nanomaterials could be applied in many fields, such as magnetic recording, biomedical, chemical catalysis and so on. The low dimensional nanomaterials properties strongly relate to its morphology and structure. However, up to now, how to synthesize the FePt nanomaterials with controllable size and morphology is still is a problem to puzzle researchers. In this work, the FePt low dimensional nanomaterials were prepared by using wet chemistry method, influences of different reaction conditions (precursor ratio, reaction temperature, and different adding amount of surfactants) on the morphology and magnetic properties of FePt nanoparticles were studied, and the growth mechanisms of the FePt low dimension nanomaterials were discussed. The main results are as follows:(1)Fe(acac)3and Pt(acac)2as precursor:the low dimensional FePt nanomaterials have been synthesized by the thermal decomposition method by using dibenzyl ether and oleyl amine (OY) as the different solvent, oleic acid (OA) and oleyl amine (OY) as the surfactants, and1,2hexadecanediol (HDD) as reducing agent. The synthesized nanomaterials are chemically disordered FCC structure. Composition of FePt nanomaterials are related to ratio of precursors. When Pt(acac)2.:Fe(acac)3is1:2, Fe, Pt atomic ratio of the synthesized materials is about1:1. With increasing the reaction temperature, FePt nanoparticles morphology changed from agglomerated worm-like to sphere-like. FePt low dimension nanomaterials with different sizes and morphologies can be prepared by changing usage amount of OY, OA and HDD.(2) Fe(CO)5and Pt(acac)2as precursor:with increasing the reaction temperature, the morphology of FePt nanoparticles changed from sphere-like to cube-like. The FePt low dimension nanomaterials with different sizes and morphologies can be prepared by tuning reaction conditions. FePt nanowires could be obtained by using oleyl amine as a solvent.(3) FePt nanomaterials growth mechanism has been discussed. Since the surfactant selectively adsorption in some crystal face, the crystal face growth would be blocked, which could lead to anisotropy growth of crystal nucleus.(4) The synthesized FePt nanomaterials have been annealed by using rapid annealing furnace (heating rate of25℃/s). Coercivity of the FePt nanomaterials obviously increased after annealing (reach to10kOe). Crystal structure of the FePt nanomaterials changed from the disordered FCC structure to the ordered structure L10structure after annealing.