Print Email Facebook Twitter Directional Excitation of a High-Density Magnon Gas Using Coherently Driven Spin Waves Title Directional Excitation of a High-Density Magnon Gas Using Coherently Driven Spin Waves Author Simon, B.G. (TU Delft QN/vanderSarlab; TU Delft QN/Quantum Nanoscience; Kavli institute of nanoscience Delft) Kurdi, S. (TU Delft QN/vanderSarlab; TU Delft QN/Quantum Nanoscience; Kavli institute of nanoscience Delft) La, Helena (External organisation) Bertelli, I. (TU Delft QN/vanderSarlab; TU Delft QN/Quantum Nanoscience; Kavli institute of nanoscience Delft; Universiteit Leiden) Carmiggelt, J.J. (TU Delft QN/vanderSarlab; TU Delft QN/Quantum Nanoscience; Kavli institute of nanoscience Delft) Ruf, M.T. (TU Delft QID/Hanson Lab) de Jong, N. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; TNO) van den Berg, J.H. (TU Delft Business Development; TU Delft QuTech Advanced Research Centre; TNO) Katan, A.J. (TU Delft QN/Afdelingsbureau; TU Delft QN/Quantum Nanoscience; Kavli institute of nanoscience Delft) van der Sar, T. (TU Delft QN/vanderSarlab; TU Delft QN/Quantum Nanoscience; Kavli institute of nanoscience Delft) Department QN/Quantum Nanoscience Date 2021 Abstract Controlling magnon densities in magnetic materials enables driving spin transport in magnonic devices. We demonstrate the creation of large, out-of-equilibrium magnon densities in a thin-film magnetic insulator via microwave excitation of coherent spin waves and subsequent multimagnon scattering. We image both the coherent spin waves and the resulting incoherent magnon gas using scanning-probe magnetometry based on electron spins in diamond. We find that the gas extends unidirectionally over hundreds of micrometers from the excitation stripline. Surprisingly, the gas density far exceeds that expected for a boson system following a Bose-Einstein distribution with a maximum value of the chemical potential. We characterize the momentum distribution of the gas by measuring the nanoscale spatial decay of the magnetic stray fields. Our results show that driving coherent spin waves leads to a strong out-of-equilibrium occupation of the spin-wave band, opening new possibilities for controlling spin transport and magnetic dynamics in target directions. Subject Magnon gasNitrogen-vacancy centersScanning-probe magnetometrySpin relaxometrySpin wavesYttrium iron garnet To reference this document use: http://resolver.tudelft.nl/uuid:72f7f05f-bb74-44d2-b858-05cc16731909 DOI https://doi.org/10.1021/acs.nanolett.1c02654 ISSN 1530-6984 Source Nano Letters: a journal dedicated to nanoscience and nanotechnology, 21 (19), 8213-8219 Part of collection Institutional Repository Document type journal article Rights © 2021 B.G. Simon, S. Kurdi, Helena La, I. Bertelli, J.J. Carmiggelt, M.T. Ruf, N. de Jong, J.H. van den Berg, A.J. Katan, T. van der Sar Files PDF acs.nanolett.1c02654.pdf 6.74 MB Close viewer /islandora/object/uuid:72f7f05f-bb74-44d2-b858-05cc16731909/datastream/OBJ/view