FePt Thin Films: Fundamentals and Applications

Recently, high magnetic anisotropy materials have received much attention to meet the demands of applications in the field of information technologies (Magnetic Films: Anisotropy). For example, in magnetic recording, as the bit size is reduced to nano dimension, material with high Ku value is needed to stabilize spin state against thermal agitation. Other applications of such materials are permanent magnet or bias layer for spin electronic devices. Among various hard magnetic materials, the equiatomic FePt ordered alloy has merged as a potential candidate for hard-disk drives with ultrahigh recording density because it has extremely high-magnetic-anisotropy energy, Ku (108 erg/cc). This high magnetic anisotropy energy allows for thermally stable grain size down to 3 nm. Thus, the FePt ordered alloy may lead to the realization of a magnetic medium capable of recording densities beyond 1 Tb in−2 (Weller et al. 2000). In addition, due to the high Pt content, FePt alloy exhibits a very good corrosive and wear resistance. Nevertheless, a disadvantage of this material for practical applications is the relative high cost of Pt. Moreover, high temperature treatment is needed to obtain FePt films with high magnetic anisotropy. Consequently, there is now a search for methods to reduce the required temperatures. This article will briefly describe different methods which have been proposed for controlling the growth of FePt thin films, reducing the temperatures of treatment as well as tailoring the properties of FePt thin films for a desired application.