2016/02/29 by Akashdeep Kamra, Wolfgang Belzig · 1 citation
Physics and Astronomy · #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.116.146601
published as Phys. Rev. Lett. 116, 146601 (2016) · 4 pages, 2 figures
arxiv created 2016/04/12 · arxiv updated 2016/04/14
The magnetization of a ferromagnet (F) driven out of equilibrium injects pure spin current into an adjacent conductor (N). Such F|N bilayers have become basic building blocks in a wide variety of spin based devices. We evaluate the shot noise of the spin current traversing the F|N interface when F is subjected to a coherent microwave drive. We find that the noise spectrum is frequency independent up to the drive frequency, and increases linearly with frequency thereafter. The low frequency noise indicates super-Poissonian spin transfer, which results from quasi-particles with effective spin ℏ^* = ℏ (1 + δ). For typical ferromagnetic thin films, δ∼ 1 is related to the dipolar interaction-mediated squeezing of F eigenmodes.