Abstract Scope |
We have worked in the past decades on bottom-up approaches to produce nanoparticles, nanorods/nanowires with high magnetic anisotropy including shape anisotropy. The approaches start from synthesis of ferromagnetic nanoparticles with modified solvothermal and other novel synthesis techniques. We have successfully synthesized monodisperse nanorods, nanowires and submicron chips of ferromagnetic FeCo, FePt, CoNi, CoCx and Co based materials. Randomly oriented nanorod/nanowire assemblies show decent room temperature coercivity for their shape anisotropy, while alignment of the rods/wires significantly enhances the magnetic hardening. The aligned Co nanowires have their coercivity values exceeding 12 kOe, comparable to rare-earth permanent magnets. In view of the conventional AlNiCo permanent magnets that have been used for many decades, these types of nanorods/wires may be used as building blocks for advanced bulk and thin film permanent magnets with reduced materials cost and improved thermal stability in the future. |