Unusual magnetization reversal in [Co/Pt]4 multilayers with perpendicular anisotropy

Unusual magnetization reversal of [Co(4 angstrom)/Pt(10 angstrom)](4) multilayers with perpendicular magnetic anisotropy has been revealed macroscopically by magnetometry measurements and microscopically by magneto-optical Kerr effect microscopy and magnetic force microscopy (MFM) imaging. During the first-order reversal process, the magnetization first decreases, then reaches a plateau, and finally rises back to saturation, corresponding to expanding bubble domains, stationary domains, and fading contrast but unchanged boundary domains, respectively. MFM imaging reveals the existence of many submicron-scaled unreversed channels within the boundary of the "bubble" domains. The magnetization reversal behavior can be accounted for by the evolution of the unusual domain structures in different field regimes. (C) 2006 American Institute of Physics.