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

摘要

We calculate the electronic structures of FePt and Fe_(0.5)Mn_(0.5)Pt 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-x)Mn_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/cm~3 and magnetocrystalline anisotropy constant (K) in the range of 9.96-8.36 × 10~6J/m~3 at OK. Temperature dependent M(T) and K(T) of Fe_(1-x)Mn_xPt (0.0294 ≤x ≤ 0.0713) were calculated using the Brillouin function and Callen-Callen experimental relation, respectively. Fe_(1-x)Mn_xR (0.0294≤x≤0.0713) shows 930-800 emu/cm~3 of M_s and 7.18-5.61 × 10~6J/m~3 of K at 300K, thereby satisfying desired magnetic properties for heat-assisted magnetic recording media to achieve 4 Tb/in.~2 areal density.