Above-Room-Temperature Ferromagnetism in Thin van der Waals Flakes of Cobalt-Substituted Fe5GeTe2

• DOI: 10.1021/acsami.2c18028
• Publication Date: 2023-01-05T16:16:48Z
• Authors: Hang Chen; Shahidul Asif; Kapildeb Dolui; Yang Wang; Jeyson Támara-Isaza; V. M. L. Durga Pr...; Matthew Whalen; Xinhao Wang; Zhijie Chen; Huiqin Zhang; Kai Liu; Deep Jariwala; M. Benjamin Jungf...; Chitraleema Chakr...; Andrew F. May; Michael A. McGuire; Branislav K. Nikolic; John Q. Xiao; Mark J. H. Ku
• Keywords: 01 natural sciences; 0104 chemical sciences

Two-dimensional (2D) magnetic van der Waals materials provide a powerful platform for studying fundamental physics of low-dimensional magnetism, engineering novel phases, and enabling ultrathin highly tunable spintronic devices. To realize high quality practical devices such applications, there is critical need robust 2D magnets with ordering temperatures above room temperature that can be created via exfoliation. Here the study exfoliated flakes cobalt substituted Fe5GeTe2 (CFGT) exhibiting magnetism reported. Via quantum imaging nitrogen-vacancy centers in diamond, ferromagnetism at was observed CFGT as thin 16 nm. This corresponds to one thinnest room-temperature magnet from single crystals, reaching thickness relevant applications. The Curie Tc ranges 310 K flake studied 328 bulk. investigate prospect high-temperature monolayer ferromagnetism, Monte Carlo calculations were performed which predicted value ~270 monolayers. Pathways towards further enhancing are discussed. These results support promising high-quality