Abstract
In order to enhance perpendicular magnetic recording characteristics of an Fe-Co-O medium with a large perpendicular anisotropy, an Fe-Co underlayer with a coercive force of about 100 Oe has been investigated. The reproduced voltage of the Fe-Co-O/Fe-Co double-layered medium with the most suitable film thickness is five times as large as that of the single-layered medium. However, the Fe-Co-O/Ni-Fe double-layered medium whose underlayer has higher permeability did not show such great improvement in reproduced voltage. These results suggest that the effect of the Fe-Co underlayer is different from the decrease of demagnetization field caused by the Ni-Fe layer in the Co-Cr/Ni-Fe double-layered medium. It has also been clarified that the Fe-Co-O/Fe-Co double-layered flexible disk has high wear resistance of more than 10 million passes without a protection layer because of the higher stiffness and stronger adhesive force existing between the Fe-Co layer and polyimide substrate.
