Tailoring magnetic properties of core/shell nanoparticles

The magnetic properties of a bimagnetic core/shell nanoparticle system with ferromagnetic FePt core and thickness-tunable, ferrimagnetic MFe 2O 4 shell were described. A single-phase-like smooth variation of magnetization with field, indicating that the core and the shell were effectively exchange coupled and magnetization of core and shell reverses cooperatively. The coercivity of the FePt/Fe 3O 4 particles depend on the volume ratio of the hard and soft phases. The results show that the magnetic properties of the core/shell nanoparticles was readily controlled by tuning the core/shell geometrical parameters and chemical composition.