Inducing formation of L10-phase in concave-cube FePt nanoparticles by annealing under high magnetic field

Abstract

Concave-cube FePt nanoparticles (NPs) with anisotropy of shape and element were annealed under high magnetic field (HMF). The high temperature sphered the FePt NPs, and Pt content and grain size of the NPs were decreased during annealing process. The HMF strength didn’t affect the shape, size and composition of the FePt NPs, but induced the formation of L 1 0 -phase in the annealed NPs. The content and ordering degree of L 1 0 -phase increased with enhancing the HMF strength, which leaded to the increasing of coercivity in the annealed FePt NPs. This work suggests that application of the HMF annealing is an effective strategy to tune the microstructure and property of anisotropic FePt NPs.