SmCo5/Fe nanocomposites synthesized from reductive annealing of oxide nanoparticles

Hard magnetic nanocomposites SmCo5/Fe-x (x=0-2.9) are synthesized by a simultaneous calcium reduction of Sm-Co-O and Fe3O4 nanoparticles. The composites consist of nanostructured SmCo5 and Fe with their average grain sizes at 29 and 8 nm, respectively. The magnetic properties of the composites can be tuned by controlling Fe composition. SmCo5/Fe-1.5 shows an enhanced remanent magnetization at 56 emu/g (45 emu/g for SmCo5). The largest coercivity value of 11.6 kOe is achieved with SmCo5/Fe-0.23. The synthesis represents a general process toward SmCo-based exchange-spring nanocomposites for high performance permanent magnet applications. (C) 2007 American Institute of Physics.