Near-Field Recording Media With Nanocomposite Cover-Layer

A nanocomposite cover-layer and a hybrid cover-layers consisting of a nanocomposite and a dielectric protective film are coated on the media for cover-layer incident near-field recording (NFR). The refractive index of the cover-layer should be matched with the effective numerical aperture of a solid immersion lens (SIL) system. The nanocomposite composed of polymer binder and nano particles is a suitable material to increase the refractive index. A collision problem in the interface between the SIL and the nanocomposite cover-layer in the NFR media yields damages after gap servo tests using a homemade gap servo NFR system. The scratch problem owing to the damages is attributed to a rough surface and brittle characteristics of the nanocomposite cover-layer. Coating a dielectric protective film on the nanocomposite layer results in a stable gap servo, in which the mechanical properties of the cover-layer are compensated by the dielectric film. However, the surface roughness problem not only in the nanocomposite but also in the hybrid cover-layers should be improved.