Tailoring magnetism in self-intercalated Cr1+δTe2 epitaxial films

Magnetic transition metal dichalcogenide (TMD) films have recently emerged as promising candidates in hosting novel magnetic phases relevant to next-generation spintronic devices. However, systematic control of the magnetization orientation, or anisotropy, and its thermal stability characterized by Curie temperature (T-C), remains to be achieved in such films. Here we present self-intercalated epitaxial Cr1+delta Te2 films as a platform for achieving systematic/smooth magnetic tailoring in TMD films. Using a molecular-beam epitaxy based technique, we have realized epitaxial Cr1+delta Te2 films with smoothly tunable delta over a wide range (0.33-0.82), while maintaining NiAs-type crystal structure. With increasing delta, we found monotonic enhancement of T-C from 160 to 350 K, and the rotation of magnetic anisotropy from out-of-plane to in-plane easy-axis configuration for fixed film thickness. Contributions from conventional dipolar and orbital moment terms are insufficient to explain the observed evolution of magnetic behavior with delta. Instead, ab initio calculations suggest that the emergence of antiferromagnetic interactions with delta, and its interplay with conventional ferromagnetism, may play a key role in the observed trends. This demonstration of tunable T-C and magnetic anisotropy across room temperature in TMD films paves the way for engineering different magnetic phases for spintronic applications.