Emergent, Non‐Aging, Extendable, and Rechargeable Exchange Bias in 2D Fe3GeTe2 Homostructures Induced by Moderate Pressuring. Issue 1 (18th November 2022)

• Record Type: Journal Article
• Authors: Liu, Caixing; Zhang, Huisheng; Zhang, Shunhong; Hou, De; Liu, Yonglai; Wu, Hanqing; Jiang, Zhongzhu; Wang, HuaiXiang; Ma, Zongwei; Luo, Xuan; Li, Xiaoyin; Sun, Yuping; Xu, Xiaohong; Zhang, Zhenyu; Sheng, Zhigao
• Is Part Of: Advanced materials. Volume 35:Issue 1(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-18
• Subjects: 2D magnets -- exchange bias -- Fe 3GeTe 2 -- training effect -- van der Waals homostructures; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202203411
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: As a crucial concept in magnetism and spintronics, exchange bias (ExB) measures the asymmetry in the hysteresis loop of a pinned ferromagnet (FM)/antiferromagnet (AFM) interface. Previous studies are mainly focused on FM/AFM heterostructures composed of conventional bulk materials, whose complex interfaces prohibit precise control and full understanding of the phenomenon. Here, the enabling power of 2D magnets is exploited to demonstrate the emergence, non‐aging, extendability, and rechargeability of ExB in van der Waals Fe3 GeTe2 homostructures, upon moderate pressuring. The emergence of the ExB is attributed to a local stress‐induced FM‐to‐AFM transition, as validated using first‐principles calculations, and confirmed in magneto‐optical Kerr effect and second harmonic generation measurements. It is also observed that, negligible ExB aging before the training effect suddenly takes place through avalanching, pronounced delay of the avalanche via timed pressure repetition (extendability), ExB recovery in the post‐training sample upon refreshed pressuring (rechargeability), and demonstrate its versatile tunability. These striking findings offer unprecedented insights into the underlying principles of ExB and its training, with immense technological applications in sight. Abstract : Upon moderate pressuring, Fe3 GeTe2 as a prototypical layered magnet transits into a ferromagnetic/antiferromagnetic coexisting state, and the homostructure with an atomically smooth interface exhibits unprecedented exchange bias (ExB) without gradual aging before collapsing via avalanching. The very existence of the non‐aging nature further allows achieving, striking and technologically significant extendability and rechargeability of the ExB.