Dresden 2017 – scientific programme

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MA: Fachverband Magnetismus

MA 64: Poster 1

MA 64.28: Poster

Friday, March 24, 2017, 09:30–13:00, P2-EG

Effect of quantum tunneling on spin Hall spin-transfer torque and spin Hall magnetoresistance — •Wei Chen¹, Seulgi Ok^1,2, Manfred Sigrist¹, Jairo Sinova³, and Dirk Manske⁴ — ¹ETH Zurich, Switzerland — ²University of Zurich, Switzerland — ³University of Mainz, Germany — ⁴Max Planck Institute for Solid State Research, Stuttgart, Germany

In the normal metal/ferromagnetic insulator bilayer (such as Pt/YIG) and the normal metal/ferromagnetic metal/oxide trilayer (such as Pt/Co/AlOx), the spin injection can be achieved by the spin Hall effect in the normal metal. We demonstrate that the quantum tunneling of spin without transferring charge is a major mechanism for the spin Hall effect induced spin-transfer torque observed in these thin films. In addition, this quantum tunneling mechanism in combination with the spin diffusion effect in the normal metal well-explain the spin Hall magnetoresistance obsered in these thin films. Our minimal model expresses these quantities in terms of generic material properties such as interface s-d coupling, insulating gap, and layer thickness, rendering an inexpensive tool for searching for appropriate materials. [1] W. Chen, M. Sigrist, J. Sinova, and D. Manske, Phys. Rev. Lett. 115, 217203 (2015). [2] S. Ok, W. Chen, M. Sigrist, and D. Manske, arXiv:1607.03409.