Tuning the Exchange Bias Effect in 2D van der Waals Ferro-/Antiferromagnetic Fe3 GeTe2 /CrOCl Heterostructures

Tianle Zhang; Yujun Zhang; Mingyuan Huang; Bo Li; Yinghui Sun; Zhe Qu; Xidong Duan; Chengbao Jiang; Shengxue Yang

doi:10.1002/advs.202105483

Tuning the Exchange Bias Effect in 2D van der Waals Ferro-/Antiferromagnetic Fe₃ GeTe₂ /CrOCl Heterostructures

Adv Sci (Weinh). 2022 Apr;9(11):e2105483. doi: 10.1002/advs.202105483. Epub 2022 Mar 3.

Authors

Tianle Zhang¹, Yujun Zhang², Mingyuan Huang², Bo Li³, Yinghui Sun⁴, Zhe Qu⁵, Xidong Duan⁶, Chengbao Jiang¹, Shengxue Yang¹

Affiliations

¹ School of Materials Science and Engineering, Beihang University, Beijing, 100191, P. R. China.
² Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, P. R. China.
³ Hunan Key Laboratory of Two-Dimensional Materials, School of Physics and Electronics, Hunan University, Changsha, Hunan, 410082, P. R. China.
⁴ Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science, School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, P. R. China.
⁵ Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China.
⁶ State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan, 419982, P. R. China.

Abstract

The exchange bias effect is extremely expected in 2D van der Waals (vdW) ferromagnetic (FM)/antiferromagnetic (AFM) heterostructures due to the high-quality interface. CrOCl possesses strong magnetic anisotropy at 2D limit, and is an ideal antiferromagnet for constructing FM/AFM heterostructures to explore the exchange bias effect. Here, the exchange bias effect in Fe₃ GeTe₂ (FGT)/CrOCl heterostructures through both anomalous Hall effect (AHE) and reflective magnetic circular dichroism (RMCD) measurements is studied. In the AHE measurements, the exchange bias field (H_EB ) at 3 K exhibits a distinct increase from ≈150 Oe to ≈450 Oe after air exposure, and such variation is attributed to the formation of an oxidized layer in FGT by analyzing the cross-sectional microstructure. The H_EB is successfully tuned by changing the FGT/CrOCl thickness and the cooling field. Furthermore, a larger H_EB of ≈750 Oe at 1.7 K in FGT/CrOCl heterostructure through RMCD measurements is observed, and it is proposed that the larger H_EB in RMCD measurements is related to the distribution of uncompensated spins at the interface. This work reveals several intriguing phenomena of the exchange bias effect in 2D vdW magnetic systems, which paves the way for the study of related spintronic devices.

Keywords: 2D magnets; exchange bias effect; spintronics; van der Waals heterostructures.

Abstract

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