The Effect of Introduced Defects on Saturation Magnetization and Magnetic Anisotropy Field of L1 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.