[(Fe/Pt/Fe)/Ag]n多层膜低温合成分离的L10相FePt纳米颗粒

制备了［（Fe/Pt/Fe）/Ag］n多层膜,研究了不同温度退火后的微结构和磁特性.实验结果表明温度高于400℃退火后,样品开始形成L10相的FePt纳米颗粒与Ag基体的复合结构.ΔM曲线的测量表明FePt颗粒之间不存在交换作用,非常清楚地说明非磁基体Ag有效地隔离了FePt磁性颗粒.有序相的低温合成可能和多层膜结构所造成的界面扩散以及Ag层引入的界面缺陷有关,同时,Ag原子较强的迁移性以及FePt与Ag之间表面自由能的显著差异,使FePt纳米颗粒被Ag隔离. 关键词： L10相 FePt 交换作用

Formation of L10-FePt nanoparticles with the precursor of [(Fe/Pt/Fe)/Ag]n multilayer at lowered annealing temperature

Microstructure and magnetic properties of (Fe/Pt/Fe)/Ag]n multilayer films after ex situ annealing at various temperatures have been investigated. The results indicate that, the multilayer starts to transform to isolated L10-FePt nanoparticles embedded in Ag matrix after annealing at temperatures above 400℃ . The formation of the face_center tetragondal (fct) phase at relatively low tem peratures seems to relate with the rapid diffusion at the interface of "Fe/Pt/Fe " and the defects caused by Ag, and the high migration speed as well as the much smaller surface free energy of Ag leads to the separation of FePt nanoparticles , which is evidenced by the result of ΔM measurements.