The influence of annealing on magnetic properties of ultrathin cobalt film

Abstract

The influence of annealing on the magnetic properties of MBE grown Au/Co/Au(111) structures with ultrathin wedge-shaped Co layers has been studied by magnetooptical techniques. The magnetization reversal process (upon a magnetic field applied in a perpendicular direction to the sample plane as a function of Co layer thickness) was probed locally at room temperature by classical magneto-optical magnetometer and optical microscope, both based on the polar Kerr effect for the "as-deposited" sample and those annealed at 150° and 250°C.Magnetic anisotropy constants were evaluated from a set of magnetization curves measured in the magnetic field with components perpendicular and parallel to the sample plane. A drastic decrease of the coercivity field, remnant magnetization and anisotropy constants was observed for the sample annealed at 250°C. Enhanced diffusion at interfaces, induced by thermal treatment, seems to be responsible for the observed effects.