Spin Seebeck effect induced by antiferromagnetic magnons and spin fluctuations in epitaxial FeF2 films

ORAL

Abstract

Recently, the spin Seebeck effect (SSE) in antiferromagnetic (AFM) Cr2O3 and MnF2 has been reported and the signals were found to rise significantly above the spin-flop (SF) field. However, it is still unclear whether the SSE requires an induced magnetic moment or just the presence of AFM magnons. Here we report a study of the SSE of FeF2/Pt heterostructures in which FeF2 is an insulating AFM epitaxial film. The high SF field (42 T) of FeF2 makes it a perfect candidate for studying the SSE below the SF field. The AFM properties of FeF2 film are characterized by exchange bias. The SSE signal of FeF2/Pt under different magnetic fields shows very similar temperature-dependent behaviors. First, there is a peak at around 11.6 K due to AFM-magnons’ contribution. Second, we observe a “bump” at the AFM ordering temperature (70 K), beyond which the SSE signal decays and persists up to 250 K under high magnetic fields, indicating that short-range spin fluctuations also contribute to the SSE signal.

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Presenters

  • Junxue Li

    University of California, Riverside, Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA, Physics and Astronomy, University of California, Riverside, Department of Physics and Astronomy, University of California, Riverside, Physics and Astronomy, UC riverside

Authors

  • Junxue Li

    University of California, Riverside, Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA, Physics and Astronomy, University of California, Riverside, Department of Physics and Astronomy, University of California, Riverside, Physics and Astronomy, UC riverside

  • Zhong Shi

    School of Physics Science and Engineering, Tongji University, Shanghai 200092, China

  • Victor Ortiz

    Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA, Physics and Astronomy, University of California, Riverside, University of California, Riverside, Physics and Astronomy, UC riverside

  • Mohammed Aldosary

    Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA, University of California, Riverside

  • Cliff Chen

    Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA, University of California, Riverside, Physics and Astronomy, UC riverside

  • Peng Wei

    University of California, Riverside, Phyiscs and Astronomy, UCR, Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA, Physics and Astronomy, UC riverside

  • Jing Shi

    University of California, Riverside, Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA, Physics, UCR, Physics and Astronomy, University of California, Riverside, Physics and Astronomy, UC riverside