Magnetic properties and texture of sputtered Fe/Fe3O4 multilayer films

Polycrystalline Fe/Fe₃O₄ multilayers have been fabricated with varying Fe/Fe₃O₄ ratios, period (bilayer) thickness, number of periods, and deposition sequence. The films were deposited by RF magnetron sputtering. The coercivity was found to vary in a nonlinear fashion between that of Fe and Fe₃ O₄. For selected multilayer geometries, the coercivity can be increased beyond that of single-layer Fe and Fe₃O₄ films. The magnetic saturation was observed to follow a linear mixture rule. These results suggest that a multilayer approach is useful for designing magnetic thin films and may allow fabrication of new materials for recording media applications. A secondary result was the ability to obtain highly textured polycrystalline films of both Fe and Fe₃O₄ on amorphous substrates for selected multilayer geometries. The texture results, which may be generally applicable, suggest that relatively thin multilayers of only a few periods may provide a means to control polycrystalline film texture on amorphous substrates