Phase-pure two-dimensional FeₓGeTe₂ magnets with near-room-temperature Tc

• Main Authors: Nair, Govindan Kutty Rajendran, Zhang, Zhaowei, Hou, Fuchen, Abdelaziem, Ali, Xu, Xiaodong, Yang, Steve Wu Qing, Zhang, Nan, Li, Weiqi, Zhu, Chao, Wu, Yao, Heng, Weiling, Kang, Lixing, Salim, Teddy, Zhou, Jiadong, Ke, Lin, Lin, Junhao, Li, Xingji, Gao, Weibo, Liu, Zheng
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Materials; van der Waals; Ferromagnetism
• Online Access: https://hdl.handle.net/10356/156077
• Institution: Nanyang Technological University

Two-dimensional (2D) ferromagnets with out-of-plane (OOP) magnetic anisotropy are potential candidates for realizing the next-generation memory devices with ultra-low power consumption and high storage density. However, a scalable approach to synthesize 2D magnets with OOP anisotropy directly on the complimentary metal-oxide semiconductor (CMOS) compatible substrates has not yet been mainly explored, which hinders the practical application of 2D magnets. This work demonstrates a cascaded space confined chemical vapor deposition (CS-CVD) technique to synthesize 2D FexGeTe2 ferromagnets. The weight fraction of iron (Fe) in the precursor controls the phase purity of the as-grown FexGeTe2. As a result, high-quality Fe3GeTe2 and Fe5GeTe2 flakes have been grown selectively using the CS-CVD technique. Curie temperature (TC) of the as-grown FexGeTe2 can be up to ∼ 280 K, nearly room temperature. The thickness and temperature-dependent magnetic studies on the Fe5GeTe2 reveal a 2D Ising to 3D XY behavior. Also, Terahertz spectroscopy experiments on Fe5GeTe2 display the highest conductivity among other FexGeTe2 2D magnets. The results of this work indicate a scalable pathway for the direct growth and integration of 2D ternary magnets on CMOS-based substrates to develop spintronic memory devices. [Figure not available: see fulltext.].