DEVELOPMENT OF MULTILAYER NANOCOATINGS FOR DATA STORAGE APPLICATIONS

Abstract

In the recent past, magnetic materials have become increasingly important in the area of information storage. Actually magnetic recording has become virtually the universal technology for the storage of information. There are two principal methods of magnetic media — particulate and thin film. The advantage of using thin film is that it provides higher storage capacities at lower costs. It is normally formed as multilayered structure, a substrate layer and upon which the thin film is made. The storage density of thin film is greater than for particulate media because the packing efficiency of thin film is greater than for the acicular particles. Many conventional and advanced technological applications require the use of materials that not only posses certain characteristic bulk properties but also specific surface properties. The surface properties can be achieved by adopting various techniques to modify the surfaces of the bulk material. Alternatively a layer of different material can be deposited onto the bulk substrate to provide surface properties. The coatings are used for many applications such as antireflective coatings, decoration, waveguides, electrical insulation and conduction, memory storage media, diffusion barrier, oxidation and corrosion barriers, gas and liquid sensors, wear-resistant coatings, hard coatings, adhesion layers, heat sinks and barriers. Nanostructured films and coatings can be fabricated using many methods that commonly fall within either vapor phase deposition or solution phase deposition. There are two types of magnetic recording mode: longitudinal and perpendicular magnetic recording. The principle, perpendicular recording media can support higher recording areal density than longitudinal ones. The film microstructural and magnetic properties are modified or controlled by the well-designed layered structure is an effective approach to tailor the film properties. The original film media design mainly depends on the good control of the under layer for both preferred orientation and grain size control. Recently, it has been found that inserting an additional layer such as seed layer or intermediate layer may improve the microstructure and magnetic properties of the media films significantly.