Exchange-Coupling of Hard/Soft Magnetic Phases of Co/FeCo Nanocomposites

Co/FeCo nanocomposites with improved magnetic performances were successfully fabricated via a liquid-phase approach. Accordingly, cobalt nanoparticles were previously prepared as hard phases by the modified polyol method, then the FeCo was deposited on cobalt nanoparticles through an electroless plating process to construct exchange-coupled nanocomposites, with controlled hard/soft phase ratios. Magnetic measurements show that the Co/FeCo nanocomposite with an optimal mass ratio of 1/2 has significantly enhanced saturation magnetization (119.14 emu.g(-1)) and remanence, which is 21.9% higher than that of a single component. More, the unkinked hysteresis loop and single-phase magnetization behavior further prove the sufficient exchange coupling effect between hard and soft nanograins. This presents the great potential of this type of nanocomposite as high performance exchange-spring magnets.