MAGNETIC FORCE MICROSCOPY OF CO-PD MULTILAYERS WITH PERPENDICULAR ANISOTROPY

The domain structure of sputtered Co-Pd multilayer films of varying th ickness has been investigated by magnetic force microscopy. The domain s appear as stripe domains, typical of perpendicularly oriented films. The size of the domains was strongly influenced by the thickness of t he film. The domain repetition lengths give an additional experimental parameter which has been used to provide a stronger test of a theoret ical model developed for ferromagnetic multilayer films [H. J. G. Draa isma and W. J. M. de Jonge, J. Appl. Phys. 62, 3318 (1987)]. It is fou nd that the experiment and theory are broadly in agreement provided th at the increased magnetization of the multilayer caused by polarizatio n of the Pd is accounted for. There is a noticeable difference between the variation of the measured and theoretical domain repetition lengt hs with film thickness. This is attributed to the effects of domain-wa ll pinning which is not considered in the model. It is estimated that the characteristic length of the films is 55 angstrom and the domain-w all-energy is 14 mJ/m2.