CoPt and FePt thin films for high density recording media

Abstract

Granular CoPt/C and FePt/C films, consisting of nanoparticles of the highly anisotropic fct CoPt (FePt) phase embedded in a carbon matrix, were made by co-sputtering from pure Co 5 oPt 50 (Fe 5 oPt 5 o) and C targets using a tandem deposition mode. The as-made films showed a disordered face centered cubic (fcc) structure, which was magnetically soft and had low coercivity. Magnetic hardening occurred after heat treatment at elevated temperatures, which led to increase in coercivity with values up to 15 kOe. The hardening originated from the transformation of the fcc phase to a highly anisotropic face centered tetragonal phase (fct) with anisotropy K > 10 7 erg/cm 3 . Transmission electron microscopy studies showed FePt particles embedded in C matrix with a particle size increasing from below 5 nm in the as-made state to 15 nm in the fully annealed state. These results are very promising and make these materials potential candidates for high-density magnetic recording.

Surfactant‐Assisted Synthesis and Characterization of Novel Chain‐Like CoNi Alloy Assemblies

“…Several kinds of magnetic anisotropy can be considered to meet this requirement, including (a) shape anisotropy of elongated magnetic particles, such as rods and wires; [7] (b) magnetocrystalline anisotropy (for example: CoPt, FePt, CuNi, FeNi 3 , etc. ); [8][9][10][11][12] and (c) exchange anisotropy of ferromagnetic/antiferromagnetic core-shell particles. [13] As important transition metal alloys, CoNi alloys have been widely used for decoration, corrosion resistance and magnetic recording devices, etc.…”

Finite-temperature magnetism ofFexPd1−xandCoPolesya1, Mankovsky2, Šipr3 et al. 2010Phys. Rev. B452370View full textAdd to dashboardCite

“…Our approach relies on a combination of ab-initio band-structure calculations with Monte Carlo (MC) simulations based on the extended Heisenberg model. To test this approach, we investigate finite-temperature magnetic properties of Pd-rich Fe x Pd 1−x alloys, with Fe concentrations up to 20 at.%, as well as of ordered and disordered Co 3 Pt, CoPt and CoPt 3 alloys that are interesting both for fundamental reasons and for possible use in industrial applications because of their high magnetic anisotropy [20,21]. Theoretical investigations of finite-temperature magnetism of these systems failed so far to reproduce experimental results with satisfactory accuracy [22].…”

Structural and Magnetic Properties of FePt and FePt-Al2O3 Thin Films

“…SiO 2 , Si 3 N 4 , BN, W etc.) into the FePt films [7][8][9][10][11][12]. We selected alumina as a matrix to dilute the interparticle exchange coupling, and decrease the grain size in the FePt-Al 2 O 3 films.…”