Thermally stable perpendicular magnetic anisotropy features of [Co/Pd]m multilayer matrix integrated with [CoO/Pd]n bottom layer

We evaluated the perpendicular magnetic anisotropy (PMA) features of a hybrid [CoO/Pd]2/[Co/Pd]7 multilayer (ML) matrix under annealing in which the [CoO/Pd]2 bottom layer was inserted. Annealing allowed for the diffusion of oxygen atoms existing in the inserted [CoO/Pd]2 layer, leading to an atomic structural reconfiguration event. The hybrid matrix was crucial to result in a higher effective anisotropy energy (3.40 Merg/cc) than an ordinary [Co/Pd]7 ML matrix (1.25 Merg/cc) under annealing at 450 °C. X-ray photoelectron spectroscopy confirmed the presence of Co-O bonding states and annealing dependent oxygen atom diffusion. The possible nature of the enhanced PMA features is discussed.