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

Co-gammaFe2O3 films have been prepared by annealing Fe3O4/CoO multilayers. The crystalline orientation of multilayers change with bilayer thickness 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 multilayers of LAMBDA < 80 angstrom have positive perpendicular anisotropy. The magnetic coercivity and the squareness of perpendicular hysteresis 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 about three times larger than that of CoFe2O4.