A thin film is a layer of material ranging from fraction of nanometers to several micrometers in thickness. The main difference between thin films and bulk is that thin films have large surface to volume ratio and thus many film properties are dominated by the surface properties of it. So the properties of thin films are most important. There is a drastic change in the magnetic, electrical mechanical and optical properties when one goes from bulk to thin films. For example, in case of optical properties of thin films there is a difference in refractive index. A bulk material that appears opaque may be fully transparent as a thin layer. Going from a bulk to a film may change some electrical properties like carrier concentration, mobility etc. Thin films are required in fields of Microelectronics (CPU processors, cell phones, iPod, watches), Solar Panels, Fuel Cells, AR (anti-reflective coatings) on cars, jewellery, mirrors, night vision goggles, Corrosion/oxidation resistance on cutting tools, chemical factories etc.
Thin Film Magnetism:
Thin film magnetism is an important field of the research in magnetism because the two dimensional nano-structures give the peculiar magnetic properties. The two dimensional nanostructures have immense possibilities to tailor their properties in order to achieve desired functionality film thickness, interface roughness, surface energies, stresses in films etc. As for application point of view, it is important to note that the properties of magnetic thin films can in part be controlled by appropriately choosing materials, growth conditions of substrate, thickness and pattern of multilayer. The magnetic properties of thin films are of high importance in magnetic data storage (hard disks as well as magnetic random-access memory) devices. In the data storage industry, the magnetic anisotropy. Magnetism has always been important for information storage, and magnetic recording is by far the largest economical application of magnetism. In multi-layers the individual layer thickness is of the order of a few nanometers. That means properties of thin film originates when mainly the surface-to-volume ratio increases and the material properties are increasingly dominated by surface and interface effects.
Magnetic Anisotropy:
The theory of ferro- and ferri-magnetism is based on electronic exchange forces. These forces are so strong that these material are spontaneously magnetized, even in the absence of an applied field. When the theory of ferromagnetism was first advanced, that ferromagnets are subdivided into many small sub-volumes, called domains. Each domain is spontaneously magnetized to saturation, but the direction of magnetization varies from domain to domain. The net vector sum of all the domains therefore produce a total magnetization of near zero. The dependence of magnetic properties on a preferred direction is called magnetic anisotropy (the influence of the crystal structure and the shape of grains on the direction of magnetization). There are several different types of anisotropy: Magnetocrystalline- Crystal Structure, Shape- Grain Shape and Stress- Applied or Residual Stresses. Magnetic anisotropy strongly affects the shape of hysteresis loops and controls the coercivity and remanence. Magnetic anisotropies play an important role in ultrathin ferromagnetic films and multilayers. Many properties of ferromagnets are directly or indirectly determined by the anisotropy, e.g., the magnetization orientation of domains, domain structure, coercivity, and the magnetization reversal process. Hence, the understanding of magnetic anisotropy and its correlation with film properties such as structure and morphology are very important for the interpretation of the magnetic behaviour of thin film structures. To more details click here Graphene Manufacturers
Thin Film Magnetism:
Thin film magnetism is an important field of the research in magnetism because the two dimensional nano-structures give the peculiar magnetic properties. The two dimensional nanostructures have immense possibilities to tailor their properties in order to achieve desired functionality film thickness, interface roughness, surface energies, stresses in films etc. As for application point of view, it is important to note that the properties of magnetic thin films can in part be controlled by appropriately choosing materials, growth conditions of substrate, thickness and pattern of multilayer. The magnetic properties of thin films are of high importance in magnetic data storage (hard disks as well as magnetic random-access memory) devices. In the data storage industry, the magnetic anisotropy. Magnetism has always been important for information storage, and magnetic recording is by far the largest economical application of magnetism. In multi-layers the individual layer thickness is of the order of a few nanometers. That means properties of thin film originates when mainly the surface-to-volume ratio increases and the material properties are increasingly dominated by surface and interface effects.
Magnetic Anisotropy:
The theory of ferro- and ferri-magnetism is based on electronic exchange forces. These forces are so strong that these material are spontaneously magnetized, even in the absence of an applied field. When the theory of ferromagnetism was first advanced, that ferromagnets are subdivided into many small sub-volumes, called domains. Each domain is spontaneously magnetized to saturation, but the direction of magnetization varies from domain to domain. The net vector sum of all the domains therefore produce a total magnetization of near zero. The dependence of magnetic properties on a preferred direction is called magnetic anisotropy (the influence of the crystal structure and the shape of grains on the direction of magnetization). There are several different types of anisotropy: Magnetocrystalline- Crystal Structure, Shape- Grain Shape and Stress- Applied or Residual Stresses. Magnetic anisotropy strongly affects the shape of hysteresis loops and controls the coercivity and remanence. Magnetic anisotropies play an important role in ultrathin ferromagnetic films and multilayers. Many properties of ferromagnets are directly or indirectly determined by the anisotropy, e.g., the magnetization orientation of domains, domain structure, coercivity, and the magnetization reversal process. Hence, the understanding of magnetic anisotropy and its correlation with film properties such as structure and morphology are very important for the interpretation of the magnetic behaviour of thin film structures. To more details click here Graphene Manufacturers
No comments:
Post a Comment