FePt Magnetic Recording Media: Problems and Possibilities for Practical Use

Abstract

FePt with ordered L1 0 structure is a promising material for high-density magnetic recording media because the material has high magnetic anisotropy energy. The film is considered to show excellent thermal stability. However, the practical use of FePt media is hindered by several problems that must be solved, i.e. decrease of ordering temperature, realization of films with perpendicular magnetic anisotropy, reduction of media noise, and development of writing methods of bits on high-coercive-force media. Among these problems, the former two problems are being resolved, but the problems associated with reducing media noise and developing writing methods still remain unsolved. It is expected that these problems will be solved by introducing new ideas or methods. Hereafter it will be important to form double-layer perpendicular magnetic recording media and to estimate the read and write characteristics of the media.

Interdiffusion in Fe–Pt multilayers

“…Such thin films are attractive for high-density magnetic recording devices 9 due to the very large magnetocrystalline anisotropy of the L1 0 FePt phase. Such thin films are attractive for high-density magnetic recording devices 9 due to the very large magnetocrystalline anisotropy of the L1 0 FePt phase.…”

Lateral displacement induced disorder in L10-FePt nanostructures by ion-implantation

“…It has been reported2 that such multi-layered structure has the potential up to 5 Tb/in 2 . Hence, in order to achieve areal density beyond 5 Tb/in 2 , it is essential to have recording media based on high anisotropy materials such as FePt in combination with BPM3456. Out of several other high anisotropy materials such as SmCo, NdFeB and CoPt, the superiority of FePt lies in an optimal combination of corrosion resistance, higher saturation magnetization and substrate temperature.…”

Switching probability sub-distributions and asymmetric magnetization reversal in FePt nanostructures

“…Thus, the present observations indicate that several independent energy barriers (de-pinning centers) can be involved also in the magnetization reversal at room temperature even though the Hall measurements presented in figure 1 can be described by a single energy barrier process. We attribute this to the different responses of the sample to the changes in the dynamics of the magnetic field application, namely 0.1 T min −1 during Hall measurements and ∼10 5 T min −1 during Kerr observations 6 . This aspect of the magnetization reversal calls for a separate study that is beyond the scope of this work; nevertheless, it serves as evidence of the appearance of multiple reversal paths not only at low temperatures but also in room temperature fast switching experiments.…”

“…The high uniaxial magnetic anisotropy in FePt [1][2][3] makes it a promising candidate for extending the current limits of magnetic recording densities without compromising the necessary thermal stability [4][5][6][7][8][9][10]. Driven by the interest in potential applications in perpendicular magnetic recording and bit-patterned media [11,12] technologies, this system has been the subject of various studies concerning magnetization reversal processes.…”

“…It is interesting to remark that asymmetric nucleation centers account for the existence of asymmetric coercive field distributions with or without considering the presence of chirality-dependent pinning [29]. 6 The device was placed at the center of a micro-coil generating 150 µs-long magnetic field pulses of various intensities. The time delay between pulses was controlled manually and was of the order of 10 s. For a better visualization of the magnetic state an image of the fully switched state (after a saturating pulse of −300 mT for (a) and 300 mT for (b)) was subtracted from all the images taken after the field pulses.…”