Synthesis and magnetic properties of Ag₂Ni₂TeO₆: Ag-based layered honeycomb Oxide.

Ag₂Ni₂TeO₆ is a layered honeycomb material comprising of Ni²⁺ ions arranged in two-dimensional honeycomb networks separated by bilayers of Ag atoms. These Ag bilayers significantly expand the interlayer spacing (≈9Å) compared to the related Na₂Ni₂TeO₆ compound and induce structural disorder through argentophilic interactions. The combination of interlayer expansion, argentophilic interactions, and structural disorder makes Ag₂Ni₂TeO₆ an ideal system to study the interplay between lattice geometry and low-dimensional magnetism. In this study we investigate the magnetic properties and crystal structure of the silver-based layered honeycomb oxide Ag₂Ni₂TeO₆, synthesized using ion-exchange reaction route in which Na₂Ni₂TeO₆ was reacted with AgNO₃ to replace Na⁺ with Ag⁺ ions. Although the precise crystallographic symmetry remains under debate, the material adopts a layered morphology consistent with a monoclinic C2/m space group and exhibits stacking disorder arising from Ag incorporation. In bulk measurements, Ag₂Ni₂TeO₆ displayed a robust magnetic lattice that remained unaffected by external magnetic fields up to 12 T. The magnetic susceptibility measurements reveal magnetic phase transition temperature at 28.6 K.