Structural and magnetic properties of the ordered FePt_3, FePt and Fe_3Pt nanoparticles

摘要

The Fe_xPt_(100- x) nanoparticles (NPs) with different nominal atomic rations (30 ≤ x≤ 80) were synthesized at 700 °C by the sol-gel method. The structure, morphology and magnetic properties of the samples were investigated. When the Fe content in the Fe-Pt alloy NPs was 30 at%, FePt_3 NPs were successfully synthesized. With the increase in Fe content up to 50 at%, it was found that the superlattice reflections (0 01) and (1 1 0) appeared, which indicated the formation of the L1_0-FePt phase. Meanwhile, the FePt_3 fraction was reduced. When the Fe content increased to 60 at%, single-phase L1_0-FePt NPs were synthesized. The coercivity (Hc), saturation magnetization (Ms) and chemical order parameter S for Fe_(60)Pt_(40) NPs were as high as 10,200 Oe, 17.567 emu/g and 0.928, respectively. With the further increase of the Fe content to 80 at%, only Fe_3Pt phase existed and the Hc of the Fe_3Pt NPs decreased drastically to 360 Oe.