Tailoring FePt-Fe3O4 exchange spring coupling magnet in silica

Journal article

The synthesis of magnetic nanoparticles has been intensively investigated not only for their electrical, optical and magnetic properties but also for their various new technological applications, such as in the areas of biology and medicine. Exchange-spring magnets are nanocomposites that are composed of magnetically hard and soft phases that interact by magnetic exchange coupling. Such systems give a major advantage of combining the permanent magnetic field with magnetization hence rendering the mixture with many unique magnetic properties compared to traditional single-phase nano-magnets. However, one major current problem encountered is to generate the stable homogeneous mixed phase nano-composites with a narrow particle distribution. Thus, the new nanocomposites can give an optimum exchange coupling for applications. Here, we report the synthesis of exchange spring coupling of FePt/Fe3Pt nanocomposites by modified polyol process. The nanocomposite is deliberately placed in silica such that the treatment could offer advantages of further stabilizing and isolating the nano-magnets from interferences by their embedment in silica during annealing. As a result, tailoring of the silica encapsulated FePt-Fe3O4 in its L10 phase can be, for the first time, demonstrated.

Authors: Yu, C; Lo, C; Tam, K; Tsang, S

• Journal: 2006 NSTI Nanotechnology Conference and Trade Show - NSTI Nanotech 2006 Technical Proceedings
• Volume: 1
• Pages: 415-418
• Publication date: 2006-01-01
• Language: English
• Keywords: Magnetic nanoparticles; Silica encapsulated iron-platinum; Exchange coupling; Energy storage