Magnetic anisotropy energy of antiferromagnetic L1₀-type equiatomic Mn alloys

The theoretical calculations of magnetic anisotropy energy (MAE) for antiferromagnetic L1₀-type MnTM [transition metal (TM)=Ni, Pd, Pt, Rh, and Ir] alloys were carried out on the basis of the local spin-density approximation using linear muffin-tin orbital method with atomic sphere approximation including the spin-orbit interaction. It has been demonstrated that the magnitude of the MAE for L1₀-type MnIr alloy is highest, -20.77 × 10⁶ J/m³, and the negative sign of the MAE is consistent with the reported spin structure. On the other hand, the sign of the MAE for L1₀-type MnPt alloy is positive in accordance with the spin structure. The MAE of the MnPt alloy is sensitive to the electron number, which would be correlated with the fact that only the MnPt alloy system exhibits a complicated magnetic phase diagram.