Determining the Magnetic Structure of a Spin-1 Kitaev Candidate Material

A family of 2D honeycomb magnets, Na₃Ni₂XO₆ (X = Sb, Bi), has garnered interest as a platform for realizing higher-spin Kitaev interactions. In Na₃Ni₂BiO₆ (NNBO), a 1/3 magnetization plateau—indicative of bond-dependent Kitaev exchange—has recently been observed, highlighting the potential of this material class to host spin-1 Kitaev physics. We propose neutron powder diffraction on Na₃Ni₂SbO₆ (NNSO), the Sb analogue of NNBO, to determine its zero-field magnetic structure. NNSO offers a unique opportunity to probe the influence of anion spin-orbit coupling on Kitaev interactions. Our single-crystal neutron data reveal a propagation vector distinct from that of NNBO, suggesting a different magnetic ground state. The proposed measurements will provide critical structural insight and inform theoretical modeling of spin-1 Kitaev systems.