Mechanism of Incommensurate Magnetic Order in BaCo 2(AsO 4) 2: Interplay of Frustrated Further-Neighbor Exchanges and Bond-Directional Anisotropy
The study investigated why BaCo2(AsO4)2 exhibits an incommensurate magnetic spiral at zero field. It found that this phase is not due to a dominant Kitaev interaction alone, but rather arises from the combined effect of exchange frustration from further-neighbor couplings (J2, J3) and intermediate bond anisotropies (Γ, Γ'). This synergy naturally explains the experimentally observed incommensurate ordering.