Tunable Sign Change of Spin Hall Magnetoresistance in $\mathrm{Pt}/\mathrm{NiO}/\mathrm{YIG}$ Structures

Tunable Sign Change of Spin Hall Magnetoresistance in $Pt / NiO / YIG$ Structures

Dazhi Hou, Zhiyong Qiu, Joseph Barker, Koji Sato, Kei Yamamoto, Saül Vélez, Juan M. Gomez-Perez, Luis E. Hueso, Fèlix Casanova, and Eiji Saitoh

Phys. Rev. Lett. 118, 147202 – Published 3 April 2017

Abstract

Spin Hall magnetoresistance (SMR) has been investigated in $Pt / NiO / YIG$ structures in a wide range of temperature and NiO thickness. The SMR shows a negative sign below a temperature that increases with the NiO thickness. This is contrary to a conventional SMR theory picture applied to the $Pt / YIG$ bilayer, which always predicts a positive SMR. The negative SMR is found to persist even when NiO blocks the spin transmission between Pt and YIG, indicating it is governed by the spin current response of the NiO layer. We explain the negative SMR by the NiO “spin flop” coupled with YIG, which can be overridden at higher temperature by positive SMR contribution from YIG. This highlights the role of magnetic structure in antiferromagnets for transport of pure spin current in multilayers.

Received 24 October 2016

DOI:https://doi.org/10.1103/PhysRevLett.118.147202

Physics Subject Headings (PhySH)

Inverse spin Hall effect Spin Hall magnetoresistance Spin pumping Spintronics

Antiferromagnets Magnetic insulators Multilayer thin films

General PhysicsCondensed Matter, Materials & Applied Physics

Authors & Affiliations

Dazhi Hou^1,2, Zhiyong Qiu^1,2,*, Joseph Barker³, Koji Sato¹, Kei Yamamoto^3,4,5, Saül Vélez⁶, Juan M. Gomez-Perez⁶, Luis E. Hueso^6,7, Fèlix Casanova^6,7, and Eiji Saitoh^1,2,3,8

¹WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
²Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Japan
³Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
⁴Institut für Physik, Johannes Gutenberg Universität Mainz, D-55128 Mainz, Germany
⁵Department of Physics, Kobe University, 1-1 Rokkodai, Kobe 657-8501, Japan
⁶CIC nanoGUNE, 20018 Donostia-San Sebastian, Basque Country, Spain
⁷IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Basque Country, Spain
⁸Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan