Tunable magnetization relaxation of Fe2Cr1−xCoxSi half-metallic Heusler alloys by band structure engineering

• Main Authors: He, Shikun, Liu, Yifan, Zheng, Yuhong, Qin, Qing, Wen, Zhenchao, Wu, Qingyun, Yang, Yi, Wang, Yupu, Feng, YuanPing, Teo, Kie Leong, Panagopoulos, Christos
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2019
• Subjects: Spin Relaxation; Ferromagnetism; DRNTU::Science::Physics
• Online Access: https://hdl.handle.net/10356/106768; http://hdl.handle.net/10220/48977
• Institution: Nanyang Technological University

We report a systematic investigation on the magnetization relaxation properties of iron-based half-metallic Heusler alloy Fe2Cr1−xCoxSi (FCCS) thin films using broadband angular-resolved ferromagnetic resonance. Band structure engineering through Co doping (x) demonstrated by first-principles calculations is shown to tune the intrinsic magnetic damping over an order of magnitude, namely 1×10−2-8×10−4. Notably, the intrinsic damping constants for samples with high Co concentration are among the lowest reported for Heusler alloys and even comparable to magnetic insulator yttrium iron garnet. Furthermore, a significant reduction of both isotropic and anisotropic contributions of extrinsic damping of the FCCS alloys was found in the FCCS films with x=0.5–0.75, which is of particular importance for applications. These results demonstrate a practical recipe to tailor functional magnetization for Heusler alloy-based spintronics at room temperature.