Pure Spin Current Driven by a Thermally Induced Magnon Chemical Potential

ORAL

Abstract

A major goal of spintronics is to develop devices that rely on spin current, rather than charge current. Of the few methods for generating pure spin current in magnetic insulators (MI), the spin Seebeck effect (SSE) is an attractive method, due to its simplicity. The SSE relies on a thermal gradient to generate a nonequilibrium distribution of magnons, collective spin quasiparticles, which carry spin current. Describing these magnons requires a thermally driven magnon chemical potential, never before measured in such a nonequilibrium system. Here we report the use of Brillouin light scattering for measuring a magnon chemical potential generated by a thermal gradient in the MI yttrium iron garnet (YIG): Y3Fe5O12. Boltzmann transport analysis allows for the quantification of spin currents due to the magnon temperature and chemical potential gradients. Finally, the range of energies and wavevectors of the magnons that contribute to the spin current are identified. Experimental determination of these items will facilitate advancing the theories describing coupled heat and spin transport. Furthermore, this technique allows for the determination intrinsic spin current generating ability of an MI, not possible using previous techniques.

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Presenters

  • Kevin Olsson

    University of Texas at Austin

Authors

  • Kevin Olsson

    University of Texas at Austin

  • Kyongmo An

    École Polytechnique Fédérale de Lausanne

  • Jianshi Zhou

    Texas Materials Institute, University of Texas at Austin, University of Texas at Austin, Mechanical Engineering, University of Texas at Austin, Mechanical Engineering, University of Texas, University of Texas (Austin, USA), Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA

  • Li Shi

    University of Texas, Austin, University of Texas at Austin

  • Xiaoqin (Elaine) Li

    University of Texas at Austin, University of Texas-Austin, The University of Texas at Austin, Department of Physics and Center for Complex Quantum Systems, Univ of Texas, Austin, Department of Physics, University of Texas at Austin, TX 78712, United States, Univ of Texas, Austin, Department of Physics, The University of Texas at Austin, Department of Physics, The University of Texas at Austin, USA