A comprehensive study of magnetocrystalline anisotropy of a layered van der Waals ferromagnet $\mathrm{V}{\mathrm{I}}_3$ was performed. We measured angular dependences of the torque and magnetization with respect to the direction of the applied magnetic field within the basal $ab$ plane and a general orthogonal plane to $ab$, respectively. A twofold butterflylike signal was detected by magnetization in the orthogonal plane. This signal symmetry remains conserved throughout all magnetic regimes as well as through the known structural transition down to the lowest temperatures. The maximum of the magnetization signal and the resulting magnetization easy axis is significantly tilted from the normal to the basal $ab$ plane by ∼40°. The close relation of the magnetocrystalline anisotropy to the crystal structure was documented. In contrast, a two-fold-like angular signal was detected in the paramagnetic region within the $ab$ plane in the monoclinic phase, which transforms into a six-fold-like signal below the Curie temperature $T_{\mathrm{C}}$. With further cooling, another six-fold-like signal with an angular shift of ∼30° grows approaching $T_{\mathrm{FM}}$. Below $T_{\mathrm{FM}}$, in the triclinic phase, the original six-fold-like signal vanishes, being replaced by a secondary six-fold-like signal with an angular shift of ∼30°.

• Received 25 November 2020
• Revised 14 April 2021
• Accepted 14 April 2021

DOI:https://doi.org/10.1103/PhysRevB.103.174401