热处理对FePt纳米颗粒磁性能的影响

Effect of Annealing Treatment on Magnetic Properties of FePt Nanoparticles

摘要:

通过多重还原法制备FePt纳米颗粒，并研究不同热处理温度对其磁性能影响。XRD及TEM分析表明：所制备的FePt纳米颗粒为fcc结构，颗粒为类球形且分散性较好，尺寸在5.0 nm左右。DSC及VSM显示，高温退火处理可以使FePt纳米颗粒从无序的fcc相变成有序的fct相，随着温度的升高矫顽力变大，600 ℃时可达240 kA/m，但是在高温区（550 ℃及以上）矫顽力的变化并不明显，这主要是由高温退火过程中纳米颗粒的团聚导致的。

Abstract:

FePt nanoparticles were prepared by multi-step reduction method. Effects of annealing temperatures on the magnetic properties of the nanoparticles were investigated. The results of XRD and TEM confirm that the as-synthesized FePt nanoparticles were fcc structure and monodisperse, with spherical shape and around 5.0 nm particle size. The results of DSC and VSM show that FePt nanoparticles would change into ordered fct structure after annealing at 500 °C for 30 min from disordered fcc structure. With the temperature increasing, the coercivity was increased, which was 240 kA/m at 600 °C. However, it changed slightly in the high-temperature region (550 °C and above it), which was attributed to the agglomeration of nanoparticles during the annealing treatment.