The Effect of Introduced Defects on Saturation Magnetization and Magnetic Anisotropy Field of L1 $_{0}$ FePt

The introduction of defects into FePt is an effective method to lower the ordering temperature of L1₀ FePt. The residual defects, however, are inevitable to affect the magnetic properties of L1₀ FePt. Using first-principles calculations, we systematically study the effect of defects (vacancy, antisite and doping) on the saturation magnetization and magnetic anisotropy field of L1₀ FePt. Our results show that the Fe-rich composition has higher saturation magnetization than Pt-rich composition. The uniaxial anisotropy field decreases with the introduction of defects except for the vacancy defects which, however, are difficultly formed due to the high formation energy.