Thermal stability and magnetism of Co and Fe ultrathin films on faceted Pd/W{112} surface

The study systematically investigates the morphology, element composition, and magnetic properties of Co and Fe films on faceted Pd/W{112} upon thermal annealing. Co thin films aggregate and form 3-dimensional islands at 400-450 K, while the {112} facets are still sustained after further annealing to 900 K. Fe thin films aggregate and form 3-dimensional islands at a lower temperature, 300-350 K, and there is no observable faceted structure after annealing at 300-900 K. The Co and Fe films on Pd/W{112} reveal stable in-plane magnetism at 100 K. The magnetic coercivity (H_c) of Co and Fe films increases and decreases, respectively, when increasing the thickness. The H_c of Co films are significantly enhanced by 2-4 times after annealing at 400-450 K, but the H_c of Fe films remain invariant upon thermal annealing at 400-450 K. These comparative studies of Co and Fe films on faceted Pd/W{112} clearly reveal the significant differences between the two systems and provide valuable information for future applications.