Interfacial Spin-Orbit Coupling in Zirconium/Nickel Bilayer

Shuan-Cheng Mai^1,2,3*, Li-Hsin Chou^1,4, Wen-Yuan Li^1,2,3, Ming-Hao Lee^1,5, Chiashain Chuang⁴, Danru Qu^1,2

¹Center for Condensed Matter Sciences, National Taiwan University, Taipei, 10617, Taiwan
²Center of Atomic Initiative for New Materials, National Taiwan University, Taipei, 10617, Taiwan
³Department of Physics, National Taiwan University, Taipei, 10617, Taiwan
⁴Department of Electronic Engineering, Chung Yuan Christian University, Taoyuan, 320314, Taiwan
⁵The Key Consortium of Electron Microscopy, National Taiwan University, Taipei, 10617, Taiwan

* Presenter:Shuan-Cheng Mai, email:b08202034@ntu.edu.tw

The spin-charge interconversions through the spin Hall effect (SHE) in a heavy metal (HM), the orbital hall effect (OHE) in a light metal (LM), and the anomalous Hall effect (AHE) in a ferromagnetic metal (FM) have received much attention due to the potential application for spintronic devices. A common way to observe the OHE is through the LM/FM bilayer, where the orbital current generated in the LM layer can be detected from the spin absorption and reflection in the FM layer, which results in a positive angular dependent magnetoresistance (ADMR) for the LM/FM bilayer. In this work, a negative ADMR is observed in the LM/NM bilayer structure of zirconium (Zr) /nickel (Ni). Our analysis shows that the negative ADMR is attributed to the interfacial spin-orbit coupling, which is caused by the imbalanced spin transmission and reflection at the interface, instead of the bulk effects such as the SHE or the OHE in Zr and the AHE in Ni. Our results provide insights of spin transport at the interface of LM/FM bilayers, which highlights the importance of interfacial spin-orbit coupling in the magnetic bilayer heterostructure.

Keywords: Angular-dependent magnetoresistance, Spin-orbit coupling, Spin current, Spin accumulation