Anisotropic SmCo₅/FeCo core/shell nanocomposite chips prepared via electroless coating

Abstract

We report the preparation of anisotropic SmCo5/FeCo core/shell nanocomposite chip-like particles via an electroless coating process. The anisotropic SmCo5 nanoscale chips were first prepared by surfactant-assisted ball milling then coated with soft magnetic FeCo using cobalt sulfate (CoSO4.7H2O) and iron sulfate (FeSO4.7H2O) as metal precursors in presence of complexing agents. The influence of the soft-phase coating on the magnetic properties of the nanocomposite particles has been studied. The saturation magnetization of the composite particles increases with increasing coating while the coercivity decreases. The FeCo coated chips have an enhanced remanence (Mr = 44.5 emu/g with 16 wt % of FeCo) compared to the uncoated chips (Mr = 36.7 emu/g), indicating exchange coupling between the hard and soft phases for the optimal soft-phase coating. Results of magnetic field alignment show the strong anisotropy of SmCo5/FeCo core/shell nanocomposite particles which can be used as building blocks of high-strength anisotropic magnets.

Keywords

• core/shell nanoparticles
• anisotropic magnetic nanoparticles
• hard magnetic nanoparticles
• nanocomposite magnets
• electroless coating