Van der Waals (vdW) magnetic materials have gained significant interest for both their fundamental physics and potential spintronic applications. One vdW magnet of great interest is layered chromium ditelluride ($\mathrm{CrT}{\mathrm{e}}_2$), which hosts intrinsic ferromagnetism above room temperature. The intercalation of Cr atoms in the vdW gaps leads to a versatile family of stable $\mathrm{C}{\mathrm{r}}_{1+\delta }\mathrm{T}{\mathrm{e}}_2$ compounds with highly tunable magnetic properties. However, experimental studies show complicated and sometimes inconsistent magnetic properties when the intercalation concentration (δ) varies. In this work, we employed first-principles calculations of three representative compounds, $\mathrm{CrT}{\mathrm{e}}_2$ ($\delta =0$), $\mathrm{C}{\mathrm{r}}_{1.25}\mathrm{T}{\mathrm{e}}_2$ ($\delta =0.25$), and $\mathrm{C}{\mathrm{r}}_{1.5}\mathrm{T}{\mathrm{e}}_2$, ($\delta =0.5$) to understand the precise role of the Cr intercalation on their structural, magnetic, and electronic properties. Our calculations suggest that $\mathrm{CrT}{\mathrm{e}}_2$ favors an in-plane magnetization, whereas intercalated Cr atoms transition it to easy-axis anisotropy in $\mathrm{C}{\mathrm{r}}_{1.25}\mathrm{T}{\mathrm{e}}_2$, and then to a canted spin configuration for $\mathrm{C}{\mathrm{r}}_{1.5}\mathrm{T}{\mathrm{e}}_2$. The variation of magnetic anisotropy can be understood based on spin-orbit coupling and orbital hybridization, with $p_x-p_y$ and $p_y-p_z$ interactions dominating in $\mathrm{CrT}{\mathrm{e}}_2$ and $\mathrm{C}{\mathrm{r}}_{1.25}\mathrm{T}{\mathrm{e}}_2$, respectively, and both contributions becoming comparably weak in $\mathrm{C}{\mathrm{r}}_{1.5}\mathrm{T}{\mathrm{e}}_2$. Charge doping switches the magnetic anisotropy by modifying the Te orbital hybridization. Using a Wannier function-based tight-binding Hamiltonian and Monte Carlo simulations, we find that intercalation introduces antiferromagnetic interlayer exchange in $\mathrm{C}{\mathrm{r}}_{1.25}\mathrm{T}{\mathrm{e}}_2$ and decreases the Curie temperature. In contrast, more ferromagnetic exchange channels in $\mathrm{C}{\mathrm{r}}_{1.5}\mathrm{T}{\mathrm{e}}_2$ enhance ferromagnetism. Our results highlight the critical role of self-intercalated Cr atoms in determining magnetic order and offer magnetic engineering paths for chromium tellurides for next-generation spintronic applications.

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• Magnetic anisotropy
• Magnetic interactions
• Spin-orbit coupling
• Dichalcogenides
• Density functional theory