Theoretical study of the effect of lattice dynamics on the damping constant of FePt at finite temperature

Understanding magnetic damping behavior at finite temperatures is crucial for magnetization reversal, especially in heat-assisted magnetic recording (HAMR) media. In this paper, we calculate the intrinsic magnetic damping of L1(0)-FePt, which is the prospective HAMR media, based on the Kambersky torque correlation model and the modified frozen thermal lattice disorder approach. Using the temperature-dependent scattering rate, the magnetic damping showed nonmonotonic behavior and slightly increased with increasing temperature, indicating that the lattice vibration enhances the interband transition around the Fermi level. Comparison of our results with the previous theoretical and experimental works clarified that, because the intrinsic damping of L1(0)-FePt was always enhanced at high temperature, the reduction of the damping around the Curie temperature in the recent experiment emphasizes the importance of extrinsic contributions of damping for HAMR application.