Electronic Structure and Magnetic Properties of Mn-Substituted Fe–Pt

We have calculated the electronic structures of FePt and Fe
_0.9375
Mn
_0.0625
Pt using first principle calculations based on density functional theory within the local-spin-density approximation (LSDA). The Curie temperature (T
_c
) was calculated by a simple model based on the mean field approximation. A supercell structure, containing eight unit cells, was used to calculate the density of states. The saturation magnetization (M
_s
) and magnetocrystalline anisotropy constant (K) at 0 K, and T
_c
for Fe
_0.9375
Mn
_0.0625
Pt were calculated to be 942 emu/cm
³
, 8.24 × 10
⁶
J/m
³
, and 590 K, respectively. The temperature-dependent M(T) and K(T) of Fe
_0.9375
Mn
_0.0625
Pt were calculated using the Brillouin function and Callen-Callen experimental relation, respectively, to obtain an Ms and a K of 822 emu/cm
³
and 6.29 × 10
⁶
J/m
³
at 300 K, respectively. These values meet the required Ms and K of 800 emu/cm
³
and 5.00 × 10
⁶
J/m
³
for achieving 4 Tb/in
²
heat-assisted magnetic recording media (HAMR).