High-<i>T</i>_c Two-dimensional Ferromagnetism in Epitaxial CrTe₂ Nanofilms

Layered compounds and thin films with intrinsic 2D ferromagnetism provide extraordinary functionalities for device applications. However, 2D magnetic materials usually exhibit weak magnetic ordering temperature compared to conventional bulk magnets due to the reduced dimensionality. We report the growth and properties of a new 2D ferromagnet, CrTe₂, with an intrinsic Curie temperature (T_c) of ~250 K for thin films ranging from 3 monolayer (ML) to 15 ML. The high T_c is preserved with film thickness down to 3 ML, which is consistent with weak interlayer magnetic coupling. Using the synchrotron-based X-ray technique, the atomic magnetic moment was identified as ~3 μ_B per atom. The intrinsic T_c and atomic magnetic moments are the highest among the known 2D magnetic materials. Using angle-resolved photoemission spectroscopy (ARPES), we observed the splitting of majority and minority electronic states of the nanofilms, which indicates the spin polarized electronic structure of the 2D magnet. Our work identifies the remarkable robustness of magnetic order in epitaxial CrTe₂ nanofilms which provides an ideal material infrastructure for studying spin physics and exploring new applications of nano-spintronics.