Nonlinear spin-current enhancement enabled by spin-damping tuning

• Published in: Nature communications 2014-12, Vol.5 (1), p.5730-5730, Article 5730
• Main Authors: Sakimura, Hiroto, Tashiro, Takaharu, Ando, Kazuya
• Format: Article
• Language: English
• Subjects: 639/301/119/1001; 639/766/530/2803; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms6730

When a magnon, the quanta of a spin excitation, is created in a magnet, this quasiparticle can split into two magnons, which triggers an angular momentum flow from the lattice to the spin subsystem. Although this process is known to enhance spin-current emission at metal/magnetic insulator interfaces, the role of interacting magnons in spintronic devices is still not well-understood. Here, we show that the enhanced spin-current emission is enabled by spin-damping tuning triggered by the redistribution of magnons. This is evidenced by time-resolved measurements of magnon lifetimes using the inverse spin Hall effect. Furthermore, we demonstrate nonlinear enhancement of the spin conversion triggered by scattering processes that conserve the number of magnons, illustrating the crucial role of spin-damping tuning in the nonlinear spin-current emission. These findings provide a crucial piece of information for the development of nonlinear spin-based devices, promising important advances in insulator spintronics. Nonequilibrium magnons in a ferromagnetic insulator can generate spin current in an adjacent metal, with potential applications in spintronic devices. Here, Sakimura et al. demonstrate nonlinear enhancement of such effects via spin-damping tuning triggered by magnon-conserving scattering processes.