More Like this

1. Separation of Artifacts from Spin-Torque Ferromagnetic Resonance Measurements of Spin-Orbit Torque for the Low-Symmetry van der Waals Semi-Metal ZrTe

   Cham, Thow Min ; Karimeddiny, Saba ; Gupta, Vishakha ; Mittelstaedt, Joseph A. ; Ralph, Daniel C. ( October 2021 , ArXivorg)

   null (Ed.)

   We measure spin-orbit torque generated by exfoliated layers of the low-symmetry semi-metal ZrTe3 using the spin-torque ferromagnetic resonance (ST-FMR) technique. When the ZrTe3 has a thickness greater than about 10 nm, artifacts due to spin pumping and/or resonant heating can cause the standard ST-FMR analysis to overestimate the true magnitude of the torque efficiency by as much as a factor of 30, and to indicate incorrectly that the spin-orbit torque depends strongly on the ZrTe3 layer thickness. Artifact-free measurements can still be achieved over a substantial thickness range by the method developed recently to detect ST-FMR signals in the Hall geometry as well as the longitudinal geometry. ZrTe3/Permalloy samples generate a conventional in-plane anti-damping spin torque efficiency ξDL|| = 0.014 ± 0.004, and an unconventional in-plane field-like torque efficiency |ξFL||| = 0.003 ± 0.001. The out-of-plane anti-damping torque is negligible. We suggest that artifacts similarly interfere with the standard ST-FMR analysis for other van der Waals samples thicker than about 10 nm. 

   more » « less
2. Separation of Artifacts from Spin‐Torque Ferromagnetic Resonance Measurements of Spin‐Orbit Torque for the Low‐Symmetry Van der Waals Semi‐Metal ZrTe 3

   https://doi.org/10.1002/qute.202100111  

   Cham, Thow Min ; Karimeddiny, Saba ; Gupta, Vishakha ; Mittelstaedt, Joseph A. ; Ralph, Daniel C. ( December 2021 , Advanced Quantum Technologies)

   Spin‐orbit torques generated by exfoliated layers of the low‐symmetry semi‐metal ZrTe₃are measured using the spin‐torque ferromagnetic resonance (ST‐FMR) technique. When the ZrTe₃has a thickness greater than about 10 nm, artifacts due to spin pumping and/or resonant heating can cause the standard ST‐FMR analysis to overestimate the true magnitude of the torque efficiency by as much as a factor of 30, and to indicate incorrectly that the spin‐orbit torque depends strongly on the ZrTe₃layer thickness. Artifact‐free measurements can still be achieved over a substantial thickness range by the method developed recently to detect ST‐FMR signals in the Hall geometry as well as the longitudinal geometry. ZrTe₃/Permalloy samples generate a conventional in‐plane anti‐damping spin torque efficiency = 0.014 ± 0.004, and an unconventional in‐plane field‐like torque efficiency = 0.003 ± 0.001. The out‐of‐plane anti‐damping torque is negligible. It is suggested that artifacts similarly interfere with the standard ST‐FMR analysis for other van der Waals samples thicker than about 10 nm.

    

   more » « less
3. Spin Torque Study of the Spin Hall Conductivity and Spin Diffusion Length in Platinum Thin Films with Varying Resistivity

   https://doi.org/10.1103/PhysRevLett.116.126601  

   Nguyen, Minh-Hai ; Ralph, D. C. ; Buhrman, R. A. ( March 2016 , Physical Review Letters)
4. Spin Seebeck Imaging of Spin-Torque Switching in Antiferromagnetic Pt/NiO Heterostructures

   https://doi.org/10.1103/PhysRevX.9.041016  

   Gray, Isaiah ; Moriyama, Takahiro ; Sivadas, Nikhil ; Stiehl, Gregory M. ; Heron, John T. ; Need, Ryan ; Kirby, Brian J. ; Low, David H. ; Nowack, Katja C. ; Schlom, Darrell G. ; et al ( October 2019 , Physical Review X)
5. Proposal for a Spin-Torque-Oscillator Maser Enabled by Microwave Photon-Spin Coupling

   https://doi.org/10.1103/PhysRevApplied.16.034034  

   Hou, Justin T. ; Zhang, Pengxiang ; Liu, Luqiao ( September 2021 , Physical Review Applied)