[16p-D419-1~18] 10.2 Fundamental and exploratory device technologies for spin

▼ [16p-D419-6] Control of magnetization damping in ultrathin Co₂₅Fe₇₅ film via the change of interfacial magnetic anisotropy at the capping layer/FM layer interface

〇(D)Shugo Yoshii^1,2, Manuel Muller³, Ryo Ohshima^1,2, Matthias Althammer³, Hans Huebl³, Masashi Shiraishi^1,2 (1.Kyoto Univ., 2.CSRN, Kyoto Univ., 3.Walther-Meissner-Institute)

Keywords:magnetization dynamics, magnetization damping, magnon

Since Co₂₅Fe₇₅ has been reported to have low magnon damping comparable to that of Y₃Fe₅O₁₂ (YIG), Co₂₅Fe₇₅ has been widely studied as a media with low magnon damping like YIG. Gilbert damping constant α, which expresses the magnetization damping, in ferromagnetic film (FM) is expressed by the following equation with the FM thickness (t_FM) dependence: α = α_int + α_SPt_FM⁻¹ + β_TMSt_FM⁻², where α_int, α_SP and β_TMS are intrinsic contribution, spin pumping contribution and two-magnon scattering (TMS) contribution, respectively. The large modulation ratio of magnetization damping in ultrathin Co₂₅Fe₇₅ film with low magnetization damping can be expected via the modulation of surface magnetic anisotropy (SMA) since the TMS contribution is proportional to the square of SMA field. The SMA in the FM film is well known to be modulated by changing the buffer layer and capping layer of FM film [4]. In this study, we aimed to modulate the magnetization damping via the control of SMA field by changing MgO capping layer thickness.