Two-dimensional van der Waals ferromagnetic thin film CrTe2 with high Curie temperature and metallic conductivity

作者：Huan Zheng, Can Huang, Fanrong Lin, Jiyu Fan, Hao Liu, Lei Zhang, Chunlan Ma, Caixia Wang, Yan Zhu, Hao Yang · 发表于：Applied Physics Letters · 年份：2023 · DOI：10.1063/5.0130479 · 被引用次数：29 · 研究领域：2D Materials and Applications、MXene and MAX Phase Materials、Graphene research and applications

Two-dimensional van der Waals (2D vdW) materials have opened up an opportunity to explore an innovative spin-based magnetic nanodevice. However, controllable fabrication of 2D vdW ferromagnets with high Curie temperature remains challenging. In this paper, we reported the growth of 2D CrTe2 single-crystal films epitaxially on Al2O3 substrates using pulsed laser deposition. We find that it shows a typical paramagnetic–ferromagnetic (PM–FM) phase transition around 200 K. The precise Curie temperature and Weiss temperature are 189 and 206.7 K, respectively. The saturation magnetization reaches 73.64 emu/g for the film thickness of 30 nm. The critical exponent β = 0.329 indicates that the magnetic interactions obey the 3D-Ising model. Electronic transport measurement confirms that a CrTe2 film always remains a metallic behavior at 5 K ≤ T ≤ 320 K and the resistivity of room temperature is 1.5 mΩ/cm. The first-principles calculation uncovers that the FM ordering state mainly stems from an exchange coupling of the adjacent Cr-spin t2g polarized electrons and the metallic conductivity is due to p–d orbital hybridization between Cr and Te atoms. This work would shed new light on studying large-scale growth of 2D magnets and developing 2D magnet-based nanodevices of room temperature.