Improved overwrite performance of dual magnetic layer tape coatings

Dual coated tapes consisting of an active layer containing fine metal powder covering a non-magnetic dummy layer have been widely promoted as perhaps the ultimate flexible recording medium. However, this is not the only interesting possibility opened up by modern double-coating technology. For digital recording, overwrite is an important characteristic. We have found the combination of a high coercivity upper layer of MP with a lower coercivity underlayer to deliver superior overwrite performance. Moreover, it is found that good overwrite ratios can be achieved even when the MP layer is comparatively thick. The combination of thicker upper layer and magnetic underlayer provides higher output in the long wavelength region.