Coercivity mechanism in (Co/Pt) and (Co/Pd) multilayers

The coercivity mechanism of multilayer (Co/Pt) and (Co/Pd) is discussed based on the phenomenological micromagnetic theory and the magnetic relaxation treatment. Based on the micromagnetic theory, the pinning size of the order of a few /spl Aring/ is found for both (Co/Pt) and (Co/Pd), but about 100 /spl Aring/ for an amorphous TbFeCo film. On the other hand, the magnetic relaxation approach estimates the Barkhausen volume of the order of 10/sup -18/cm/sup 3/ for these multilayers.