Tuning non-Gilbert-type damping in FeGa films on MgO(001) via oblique deposition

Abstract

The ability to tailor the damping factor is essential for spintronic and spin-torque applications. Here, we report an approach to manipulate the damping factor of FeGa/MgO(001) films by oblique deposition. Owing to the defects at the surface or interface in thin films, two-magnon scattering (TMS) acts as a non-Gilbert damping mechanism in magnetization relaxation. In this work, the contribution of TMS was characterized by in-plane angular dependent ferromagnetic resonance. It is demonstrated that the intrinsic Gilbert damping is isotropic and invariant, while the extrinsic mechanism related to TMS is anisotropic and can be tuned by oblique deposition. Furthermore, the two and fourfold TMS related to the uniaxial magnetic anisotropy and magnetocrystalline anisotropy were discussed. Our results open an avenue to manipulate magnetization relaxation in spintronic devices.

Large anisotropy of magnetic damping in amorphous CoFeB films on GaAs(001)

“…These two studies both excluded the TMS contributions. The anisotropy of magnetic damping has been also observed in some epitaxial magnetic alloy lms, such as Co 2 FeAl [17][18][19], Co 2 FeSi [20], Co 2 MnSi [21] and FeGa [22], although whether the origin of the damping anisotropy is intrinsic or extrinsic remains controversial.…”

Perspectives: Light Control of Magnetism and Device Development

“…Previous research demonstrated that the FM damping can be modulated by tuning the interfacial spin–orbit coupling and TMS effect. , However, these works suffered from high-operation voltage (>400 V) and high energy consumption, limiting their potential applications in the future. , Transitioning from the discussion of polarized light-controlled magnetism, it is important to highlight the superiority of photovoltaic (PV) control. It operates with lower power consumption and minimal thermal impact.…”

Giant anisotropy of magnetic damping and significant in-plane uniaxial magnetic anisotropy in amorphous Co40Fe40B20 films on GaAs(001)*

“…Recently, several groups [15][16][17][18][19][20][21] reported anisotropic damping in the film plane, i.e., α could be tuned via rotating the magnetization orientation of the FM layer in the same sample. Meanwhile, the anisotropic damping is found to be accompanied with prominent in-plane magnetic anisotropies in the FM layer, e.g., twofold uniaxial magnetic anisotropy (UMA), fourfold magneto-crystalline anisotropy (MCA), or both of them.…”

“…The anisotropic magnetic damping has also been observed in some other magnetic alloy films, such as Co 2 FeAl, [18] Co 2 FeSi, [19] Co 2 MnSi, [20] and FeGa. [21] However, in all these studies, the FM layers are either single-crystalline or highly textured polycrystalline. Since MCA can be completely ruled out, amorphous FM film (e.g., CoFeB) has been found to exhibit a pure in-plane UMA after being deposited on an appropriate substrate (e.g., GaAs).…”