Magnetic properties of Co/Si(100) thin films studied using magnetooptic Kerr effect technique

Magnetic properties of cobalt films grown on a Si(100) substrate were investigated using the magnetooptic Kerr effect technique. The longitudinal coercivity for the films with a thickness range from 2.4 to 17.7 nm is observed to be approximately 55 Oe. The easy axis of magnetization is in the surface plane. Because of silicide formation at the interface and a short absorption length for light in condensed matter, the Kerr intensity is not completely proportional to the film thickness. Thermal evolution for the Co/Si(100) system was systematically investigated. A higher thermal stability is concluded for a thicker cobalt film. At a low temperature, the Kerr intensity is nearly maintained constant upon annealing treatment. This is expected to be due to the Co-Si compound at the interface blocking further interdiffusion.