Electron beam reduction induced self-assembly growth of Co/CoO nanocomposite materials

Electron beam irradiation (EBI) technology has been widely used in industrial fields during the welding process, and the instantaneous high temperature produced during this process is a significant advantage for the synthesis of metallic materials. Here, we report a method to manufacture metal/oxide nanocomposite materials by EBI using oxide films. The CoO films are first prepared by a pulsed-laser deposition technique, and the as-prepared films are treated by EBI with different electron doses. CoO can be controllably reduced to metallic Co, and a Co/CoO nanocomposite is produced with a large number of oxygen vacancies after EBI. The self-assembled well-dispersed Co nanoparticles are formed on the film surface, and their sizes can be controlled by the electron dose and irradiation time. The obtained Co/CoO composited nanoparticle films exhibit an exchange bias effect, and their blocking temperature can be modified by variations in the electron dose and time.