Bimagnetic Core/Shell FePt/Fe₃O₄ Nanoparticles

Bimagnetic core/shell Fe58Pt42/Fe3O 4 nanoparticles are synthesized from high-temperature solution phase coating of 4 nm Fe58Pt42 core with Fe3O 4 shell. The shell is tunable from 0.5 to 3 nm. Magnetic properties of the as-synthesized core/shell particles are dependent on shell thickness due to the exchange coupling between core and shell. Upon reductive annealing, an assembly of the core/shell nanoparticles is transformed into a hard magnetic nanocomposite with enhanced energy product.