Magnetic Phase Diagram of Cr2Te3: The Hidden Role of Layer Stacking

Using two-dimensional (2D) van der Waals (vdW) ferromagnets in spintronic devices can enhance their performance through well-controlled vdW interfaces and reduced power consumption. Cr2Te3 appears as a promising candidate because of its strong perpendicular magnetic anisotropy, but the Curie temperature is limited to 180 K. In this work, we use annealing in air to uncover the magnetic phase diagram of Cr2Te3. We correlate magnetic properties with layer stacking and the interlayer distance; both depend strongly on the annealing temperature. In particular, disorder in layer stacking plays a key role in the magnetic properties of Cr2Te3 and more generally of vdW ferromagnets. By annealing at 375 °C, we can eventually raise the Tc of Cr2Te3 up to 303 K in the epitaxial Cr2Te3/WSe2 vdW heterostructure with in-plane magnetic anisotropy. This work provides a simple method to control the magnetic properties of 2D ferromagnets and incorporate them into spintronics devices.