Evidence of Temperature-Dependent Interplay between Spin and Orbital Moment in van der Waals Ferromagnet VI₃

van der Waals materials provide a versatile toolbox for the emergence of new quantum phenomena and fabrication of functional heterostructures. Among them, the trihalide VI₃ stands out for its unique magnetic and structural landscape. Here we investigate the spin and orbital magnetic degrees of freedom in the layered ferromagnet VI₃ by means of temperature-dependent X-ray absorption spectroscopy and X-ray magnetic circular and linear dichroism. We detect localized electronic states and reduced magnetic dimensionality, due to electronic correlations. We furthermore provide experimental evidence of (a) an unquenched orbital magnetic moment (up to 0.66(7) μ_B/V atom) in the ferromagnetic state and (b) an instability of the orbital moment in the proximity of the spin reorientation transition. Our results support a coherent picture where electronic correlations give rise to a strong magnetic anisotropy and a large orbital moment and establish VI₃ as a prime candidate for the study of orbital quantum effects.