Ferromagnetic resonance and proximity effect in WTe2/magnetic insulator heterostructure

ORAL

Abstract

Integration of FMI films with 2D materials or topological insulators has proven to be promising for the demonstration of spin-orbit torque switching and more efficient spintronic devices. As an alternative to YIG, we have identified spinel ferrite MgAl0.5Fe1.5O4 (MAFO) for the spin source material. The Gilbert damping constant of MAFO is 0.001, similar in magnitude to typical YIG. In this work, we have realized bilayer structures of exfoliated nanometer thick WTe2 flakes on top of low damping MAFO thin films. The samples were post-annealed at 300 oC for 5 h at a vacuum pressure, giving rise to strong exchange coupling between the 2D and the MAFO layers. Raman spectroscopy showed that WTe2 maintained the desired phase after processing. Together with atomic force microscopy, the thickness of WTe2 was estimated to be several atomic layers. Magnetoresistance measurements revealed a hysteresis loop that was correlated with the magnetization curves of MAFO. These results suggest proximity-induced ferromagnetism in the WTe2 atoms at the interface. We characterized our samples with spin-torque ferromagnetic resonance. This new WTe2/magnetic insulator system is promising for future spinel ferrite insulator based spin current devices.

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Presenters

  • Peng Li

    Department of Applied Physics, Stanford University

Authors

  • Peng Li

    Department of Applied Physics, Stanford University

  • Edbert Jarvis Sie

    Physics, Massachusetts Institute of Technology, Department of Materials Science and Engineering, Stanford University, Stanford University

  • Jacob Wisser

    Department of Applied Physics, Stanford University, Geballe Laboratory for Advanced Materials, Stanford University, Applied Physics, Stanford University

  • Lauren Riddiford

    Department of Applied Physics, Stanford University, Geballe Laboratory for Advanced Materials, Stanford University, Applied Physics, Stanford University

  • Aaron Altman

    Department of Applied Physics, Stanford University

  • Aaron Lindenberg

    Department of Materials Science and Engineering, Stanford University, Stanford University

  • Yuri Suzuki

    Stanford University, Department of Applied Physics, Stanford University, Applied Physics, Stanford University, Geballe Laboratory for Advanced Materials, Stanford University