MAGNETIC AND MAGNETOOPTICAL PROPERTIES OF THE CO-GAMMA-FE2O3 PERPENDICULAR MAGNETIC-FILMS

Co-gammaFe2O3 films have been prepared by annealing Fe3O4/CoO multilay ers. The crystalline orientation of multilayers change with bilayer th ickness LAMBDA; the [100] axis of Fe3O4 and CoO orients perpendicular to the film plane for LAMBDA < 80 angstrom and the [111] axis orients for LAMBDA > 100 angstrom. The Co-gammaFe2O3 films obtained from multi layers of LAMBDA < 80 angstrom have positive perpendicular anisotropy. The magnetic coercivity and the squareness of perpendicular hysteresi s curves are about 5.0 kOe and 0.8, respectively. The films show high magneto-optical effects and the figure of merit is 5.5 deg, which is a bout three times larger than that of CoFe2O4.