Spherical microparticles, capable of responding to magnetic fields, were prepared by encapsulating dextran-coated Fe3O4 nanoparticles into chitosan poly(acrylic acid) (PAA) microspheres template. The obtained magnetic microspheres were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray powder diffra...

The remanence of an isotropic nanocrystalline exchange-coupled composite system (comprising hard and soft magnetic phases) is investigated analytically within a simple (onedimensional) micromagnetic model, in which only exchange and anisotropy energies are considered. For a soft grain with size much less than its own Bloch wall width, our analysis shows that the magnetization distribution in th...