Magnetic thin film disk

Cutiongco, E. C., Li, D., and Chung, Y. W., "Tribological Behavior of Amorphous Carbon Nitride Overcoats for Magnetic Thin-film Rigid Disks, 7. Tribol., Vol. 118, 1996, pp. 543-548. 

Mirzamaani et al. [74, 75] point out that the earlier studies of the interrelationships between structure and magnetics have examined films substantially thicker than those now being used in thin-film disks. These authors have examined very thin CoP films and have studied the relative roles of shape anisotropy, stress anisotropy, and crystal anisotropy in determining the magnetic properties. For their CoP-deposition system, shape anisotropy dominated the other factors in determining the film magnetic properties. The shape anisotropy of a particular deposit was determined by the surface condition of the substrate on which the CoP was deposited. 

Overcoats are an integral part of thin-film disk structures. Their primary role is to provide wear protection. The most common overlayers, such as Rh, plasma-polymerized coatings, SiOz, and carbon, are all chemically stable if they were fully to cover the disk surface, they would provide good corrosion resistance. The thinness of the overcoats and the roughness of the surface preclude perfect coverage and open up the path for localized corrosion at the sites where the magnetic layer is exposed to the environment. 

Underlayer (Ni-P) -10 pm Electroless deposition Fig. 48 Schematic cross section of a general electroless deposited thin-film disk magnetic recording medium. 

Fig. 50 Schematic cross section of a thin-film disk with complex, multilayer structures of magnetic layer and underlayer (from Ref. 157 with permission from American Institute of Physics).

Schematic representation of thin-film disk structure, (a) layers and thickness as of about 1999. Dimensions as of 2010 are C overcoat of 3nm, magnetic layer 20nm, under layers 60mn. (b) Schematic view of corrosion of roughened disk structure in a chloride-contaminated environment.

Kajdas, C., and Bhushan, B., Mechanism of Interaction and Degradation of PFPEs with a DLC Coating in Thin-Film Magnetic Rigid Disks A Critical Review," /. Info. Storage Proc. Syst.,Vol. 1,1999, pp. 303-320. 

Huang, P., Niu, R. J., and Hu, H. H., A New Numerical Method to Solve Modified Reynolds Equation for Magnetic [31] Head/Disk Working in Ultra Thin Gas Films, Sci. China,... 

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