Magnetic properties of Fe-Mn-Pt for heat assisted magnetic recording applications

We calculate the electronic structures of FePt and Fe_0.5Mn_0.5Pt using first-principles calculations based on density functional theory within the local-spin-density approximation. The Curie temperature (T_c) was calculated by mean field approximation. Composition dependence of the Cure temperature (T_c(x)) of Fe_1−xMn_xPt was used to identify a composition to meet the desired T_c in the range of 600–650 K. The identified composition (0.0294 ≤ x ≤ 0.0713) gives saturation magnetization (M_s) in the range of 1041–919 emu/cm³ and magnetocrystalline anisotropy constant (K) in the range of 9.96–8.36 × 10⁶J/m³ at 0 K. Temperature dependent M(T) and K(T) of Fe_1−xMn_xPt (0.0294 ≤ x ≤ 0.0713) were calculated using the Brillouin function and Callen-Callen experimental relation, respectively. Fe_1−xMn_xPt (0.0294 ≤ x ≤ 0.0713) shows 930–800 emu/cm³ of M_s and 7.18–5.61 × 10⁶J/m³ of K at 300 K, thereby satisfying desired magnetic properties for heat-assisted magnetic recording media to achieve 4 Tb/in.² areal density.