Mo P 3 Si O 11 : A 4 d 3 honeycomb antiferromagnet with disconnected octahedra

Transition metal compounds can feature different types of magnetic anisotropy. By studying a honeycomb-lattice material with disconnected transition-metal octahedra, the authors reveal the crucial role of the single-ion anisotropy term that arises despite the nominally quenched orbital moment of the ${d}^{3}$ magnetic ion. Their findings suggest that the effect of single-ion anisotropy should not be ignored when searching for signatures of Kitaev interactions in spin-3/2 honeycomb magnets.