垂直磁各向异性CoFeB-MgO相关薄膜结构的阻尼调控

CoFeB-MgO界面Fe-3d和O-2p轨道杂化产生的垂直磁各向异性，推动了磁隧道结等相关薄膜结构的研究，其应用的主要挑战在于阻尼调控。然而，CoFeB-MgO相关薄膜结构中，阻尼来源机制还不明确，本征Gilbert阻尼与垂直磁各向异性可能存在的关联尚未厘清，缺乏有效的阻尼调控手段。对此，本项目以降低本征Gilbert阻尼为目标，通过磁场、频率、角度、温度以及薄膜结构参数等调制阻尼，分析其变化规律，揭示阻尼的来源机制与贡献；研究CoFeB层及CoFeB-MgO、CoFeB-Ta界面的微观状态对阻尼及垂直磁各向异性的影响规律，通过成分调控、界面插层、热处理优化等方式降低本征Gilbert阻尼；在此基础上，厘清本征Gilbert阻尼和垂直磁各向异性之间的关联。本项目对垂直磁各向异性CoFeB-MgO相关薄膜结构在自旋电子学单元和器件中的应用具有重要意义。

Attributed to the hybridization of Fe-3d and O-2p orbitals at CoFeB-MgO interfaces, the perpendicular magnetic anisotropy has promoted the researches on the related thin film structures, such as magnetic-tunnel-junctions. The main challenge facing their applications is the tuning of damping. However, in CoFeB-MgO related thin film structures, the origin and mechanism of damping are still unclear, the possible correlation between the intrinsic Gilbert damping and the perpendicular magnetic anisotropy has not been clarified, and the effective tuning method of damping is lacking. Therefore, in this project, aiming at the reducing of intrinsic Gilbert damping, we propose to disclose the origin, mechanism and contribution of damping through the investigation and analyzing of its dependences on magnetic field, frequency, angle, temperature and the structure aspects of thin film structures. The influences of CoFeB layer and the interfaces of both CoFeB-MgO and CoFeB-Ta on damping and perpendicular magnetic anisotropy will be studied. The intrinsic Gilbert damping is going to be reduced by tuning the composition, inserting layers at interfaces, and optimizing the annealing process. Based on these studies, we will clarify the possible correlation between the intrinsic Gilbert damping and the perpendicular magnetic anisotropy. This project will contribute to the applications of these CoFeB-MgO related thin film structures with perpendicular magnetic anisotropy in spintronic units and devices.