2018/07/19 by R. J. Doornenbal, A. Roldán-Molina, Álvaro S. Núñez +2 · 29 citations
Engineering · Physics and Astronomy · #Amplitude #Condensed matter physics #Electron #Ferromagnetism #Laser #Lasing threshold #Magnetic field #Magnetic properties of thin films #Magneto-Optical Properties and Applications #Magnonics #Physics #Quantum and electron transport phenomena #Quantum mechanics #Spin (aerodynamics) #Spin Hall effect #Spin polarization #Spin wave #Spin-transfer torque #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.122.037203
published in Physical Review Letters 122(3), 037203 (American Physical Society) · 5 pages, 4 figures
arxiv created 2018/07/19 · openalex publication_date 2019/01/25 · arxiv updated 2019/01/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We show that an inhomogeneity in the spin-transfer torques in a metallic ferromagnet under suitable conditions strongly amplifies incoming spin waves. Moreover, at nonzero temperatures the incoming thermally occupied spin waves will be amplified such that the region with inhomogeneous spin-transfer torques emits spin waves spontaneously, thus constituting a spin-wave laser. We determine the spin-wave scattering amplitudes for a simplified model and setup, and show under which conditions the amplification and lasing occurs. Our results are interpreted in terms of a so-called black-hole laser, and could facilitate the field of magnonics, which aims to utilize spin waves in logic and data-processing devices.