Directional power loss in magnetic thin films guided by magnetic anisotropy from magnetic nanoparticle chains

The property of directional power absorption from a microwave magnetic field in thin anisotropic magnetic films was demonstrated. They are 2D printed magnetic nanoparticle chains on polyethylene foil (LDPE) made of single-domain Fe3O4 magnetic nanoparticles with magnetic uniaxial anisotropy. The 2D feature of the magnetic material results from the self-assembling of magnetic nanoparticles into ring-shaped chains during the drying of the magnetic colloid droplet on LDPE. Ferromagnetic resonance experiments on such thin magnetic films showed the possibility of selective dissipation of microwave magnetic field power. The experimental results were supported by computer simulations using Landau–Lifshitz–Gilbert equations. The possibility of directional power loss in the absence of a static magnetic field was also briefly discussed.