Impact of surface termination on magnetic anisotropy and Gilbert damping in L10-MnAl thin films

The magnetic properties of L10-MnAl thin films are of significant interest due to the combination of high magnetic anisotropy energy and low Gilbert damping, which play critical roles in thermal stability and low switching current (IC) in spintronic devices like spin transfer torque magnetic random access memory (STT-MRAM). In this study, we employ density functional theory (DFT) to investigate the impact of different surface terminations—Mn-terminated, Al-terminated, and Mn–Al terminated configurations on the magnetic anisotropy energy (MAE) and Gilbert damping constant (α) of L10-MnAl thin films, both in bare form and in MgO/MnAl/MgO heterostructures. The MAE was evaluated using the force theorem (FT) and α using Kambersky’s torque-torque correlation model. Our calculations reveal that surface anisotropy is influenced not only by the film thickness but also by the atomic environment of the surface layer. We found that the perpendicular magnetic anisotropy of L10-MnAl thin films is enhanced with Al-termination compared to Mn-termination. Furthermore, the calculated Gilbert damping, a key factor in spin relaxation dynamics, indicates that the density of states (DOS), hybridization, and spin–orbit coupling (SOC) at the interface significantly affect spin relaxation mechanisms. This study highlights the significance of the interfacial properties of L10-MnAl-based devices and emphasizes the importance of surface terminations in improving magnetic performance, a crucial factor for the development of high-efficiency STT-MRAM devices.