Interfacial Modulation of Spin-Orbit Torques Induced by Two-Dimensional van der Waals Material ZrSe3

Lulu Cao; Qian Chen; Yonghui Zhu; Kaiyu Tong; Wenjia Li; Jun Ma; Milad Jalali; Zhaocong Huang; Jing Wu; Ya Zhai

doi:10.1021/acsami.4c00881

Interfacial Modulation of Spin-Orbit Torques Induced by Two-Dimensional van der Waals Material ZrSe₃

ACS Appl Mater Interfaces. 2024 Apr 17;16(15):19764-19770. doi: 10.1021/acsami.4c00881. Epub 2024 Apr 5.

Authors

Lulu Cao¹, Qian Chen¹, Yonghui Zhu¹, Kaiyu Tong², Wenjia Li², Jun Ma², Milad Jalali¹, Zhaocong Huang¹, Jing Wu², Ya Zhai¹

Affiliations

¹ Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, Jiangsu 211189, People's Republic of China.
² Department of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom.

PMID: 38577833
DOI: 10.1021/acsami.4c00881

Abstract

Two-dimensional van der Waals (2D vdW) materials are widely used in spin-orbit torque (SOT) devices. Recent studies have demonstrated the low crystal symmetry and large spin Hall conductivity of 2D vdW ZrSe₃, indicating its potential applications in low-power SOT devices. Here, we study the interfacial contribution of SOTs and current-induced magnetization switching in the ZrSe₃/Py (Ni₈₀Fe₂₀) and ZrSe₃/Cu/Py heterostructures. SOT efficiencies of samples are detected by the spin-torque ferromagnetic resonance (ST-FMR), and out-of-plane damping-like torque (τ_B) is observed. The ratio between τ_B and the field-like torque (τ_A) decreases from 0.175 to 0.138 when inserting 1 nm Cu at the interface and then drops to 0.001 when the thickness of Cu intercalation is 2 nm, indicating that Cu intercalation inhibits the τ_B component of SOT. Moreover, the SOT efficiency is increased from 3.05 to 5.21, which may be attributed to the Cu intercalation being beneficial to improve the interface between Py and ZrSe₃. Theoretical calculation has shown that the Cu spacer can change the conductivity of ZrSe₃ from semiconductor to conductor, thereby decreasing the Schottky barrier and increasing the transmission efficiency of the spin current. Furthermore, magneto-optical Kerr effect (MOKE) microscopy is employed to verify the current-driven magnetization switching in these structures. In comparison to the ZrSe₃/Py bilayer, the critical current density of ZrSe₃/Cu/Py is reduced when inserting 1 nm Cu, demonstrating the higher SOT efficiency and lower power consumption in ZrSe₃/Cu/Py structures.

Keywords: 2D vdW material ZrSe3; SOT efficiency; critical current density; current-driven magnetization switching; density function theory; spin−orbit torque.