Thin film disks

Fig. 1. Typical structures of storage media. Top a particulate disk. Center a thin-film disk. Bottom ...

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. 

Electrochemical science and technology have played an important role in all aspects of the new technology of the thin-film disk, which is capable of higher storage density than the particulate disk. The first disks, at the beginning of the technology more than... 

V Brusic, J. Horkans, and D. J. Barklay offer an authoritative review of the electrochemical aspects of fabrication and of evalution of the stability of thin film storage media. Recent developments have led to improved thermodynamic stability, thereby rendering thin film disks suitable for high density storage applications. 

T. E. Karis, G. W. Tyndall, and R. J. Waltman, Lubricant bonding effects on thin film disk tribology, Tribol. Trans. 44(2), 249-255 (2001). 

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).

Tsang C et al (1990) Gigabit density recording using dual-element MR inductive heads on thin-film disks. IEEE Trans Magn MAG-26 1689-1693... 

Figure 3 (a) Schematic representation of thin-film disk stmcture. (b) Schematic view of corrosion of roughened disk stmcture in a chloride-contaminated environment... 

Figure 10 Potentiodynamic polarization curves of thin-film disk materials in a droplet of DI water. Parameter definitions DCC DC sputtered C RFC RF sputtered C CoCr, Co + 17%Cr CoP, CO + 8%P Co, pure Co. (From Ref 135.)...

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