Coexisting long-range zigzag antiferromagnetic order and glassy dynamics in spin-1 honeycomb lattice Na3Ni2SbO6.

Here, we report an interesting magnetic oxide NaNiSbO, where the interplay between exchange interactions and lattice symmetry crucially influence its exotic ground state (GS). This compound features a layered honeycomb lattice with magnetic Ni(spin-1) surrounding nonmagnetic Sbcenters. The x-ray absorption and magnetic circular dichroism measurements confirm a Nicharge state with notable spin and orbital moments at room temperature. The material exhibits antiferromagnetic (AFM) ordering around 17 K () and a field-induced magnetic transition at lower temperatures. Our measurements reveal a low-temperature anomaly, likely linked to glassy behavior. The power-law magnetic specific heat suggests mixed magnon dispersion, while low magnetic entropy indicates a highly degenerate GS. Neutron diffraction data point to a zigzag-type AFM GS, with a reduced site moment of 1.34(3)at 2.5 K that disappears near 17.2 K, consistent with bulk data. Lattice parameters show anomalies atand lower temperatures. Ab-initio calculations support zigzag spin order and imply a competing in-plane Niinteractions that causes spin frustration. Overall, our combined experimental and theoretical study uncovers the microscopic magnetic GS of NaNiSbOas a mix of long-range zigzag AFM and a glassy state, advancing the understanding of frustrated honeycomb magnets.